Sonia Nevermind

Early Life

Sonia is the princess of a small European kingdom called Novoselic. She lived a comfortable life inside the royal castle, with many servants serving her a variety of Japanese dishes and doing all the cleaning. As a result, she never experienced such dirty work herself and was cared for so thoroughly that it took her a long time to learn how to do simple tasks. In her Island Mode, she revealed that she did a lot of princessy activities since childhood, such as riding horses and carriages. When she felt like being alone, Sonia had a habit of secretly leaving the castle to hide and read in the national library. She became so good at hiding that she nearly died while participating in a hide-and-seek tournament in the royal library as no one could find her, leading to its cancellation.

As it was her destiny to one day rule her kingdom, Sonia received an extensive education required for a royal family member, making her fluent in 30 foreign languages and highly knowledgeable in various fields such as the Novoselic culture, economics, international law, and diagnostic medicine. In addition, she became accustomed to her country's military, likening a place such as the Jabberwock Island's military base to be a place she grew quite tired and bored of. Brushing with death was not a new experience for Sonia as she was abducted twice by insurgents in the past.

From her genteel upbringing, Sonia became quite sheltered as she never had a friend of equal standing. Furthermore, she lacked personal freedom and must dedicate most of her time to her country and its people—a princess before she is a person. This made her look forward to attending Hope's Peak Academy as the Ultimate Princess of Class 77-B, an opportunity for her to experience life as an ordinary girl. She had also dedicated much of her free time to studying Japanese culture and eventually became fluent in the language, attributing her love for Japanese dramas as the main reason. Before her foreign exchange to Japan, Sonia attended In Utero School in her home country.

Attending Hope's Peak Academy

Sonia was one of the few students in Class 77-B who attended class regularly, although attendance was not mandatory for Ultimates. Inspired by her homeroom teacher, Chisa Yukizome, Sonia joined her efforts to bring the class together and successfully helped gather all of her classmates. From that point onward, Sonia followed Chisa's wish for her students to build strong relationships and "hope" among each other. She participated in various activities with her classmates, such as repairing and cleaning their classroom, playing video games, having lunch, relaxing at the park, and collectively electing Chiaki Nanami, the Ultimate Gamer, as their class representative.

Alongside their happy moments, Sonia also shared the pain her classmates endured. She was affected by the murder of Natsumi Kuzuryu and Sato, the younger sister of Fuyuhiko Kuzuryu, the Ultimate Yakuza, and the best friend of Mahiru Koizumi, the Ultimate Photographer, respectively. Sonia was also devastated upon learning that Chisa had been put on a probationary transfer to the Reserve Course Department for a semester, taking responsibility for the subsequently suspended Nagito Komaeda, the Ultimate Lucky Student, after his involvement in a bombing incident during a practical exam.

Once Chisa returned, Sonia and her classmates held a welcome-back party for her. During her homeroom teacher's absence, Sonia had grown particularly close to Gundham Tanaka, the Ultimate Breeder, due to their complementary interest in the occult. Sonia even picked up Gundham's unique manner of speaking and habits, and the two were able to synchronize their movements.

Second Year

In her upperclassman year, Sonia continued to bond with Gundham, though he still referred to her as a low-ranked demon, especially after he claimed that his Grizner would only attack demons of significantly higher rank. Around the same time, Sonia and her classmates noticed from their building that the students from the Reserve Course students had launched a massive protest against the Main Course, blaming them for causing the Tragedy of Hope's Peak Academy. Unbeknownst to most, the true mastermind behind the tragedy was Junko Enoshima, the originator of Ultimate Despair, who manipulated events behind the scenes and framed Izuru Kamukura—the result of the Izuru Kamukura Project—for the incident. The Hope's Peak Academy committee, responsible for the project, was accused of using the exorbitant fees paid by Reserve Course students to create so-called 'murderers'.

Although Sonia and her classmates were seemingly unrelated to the growing protest, they became involved after noticing that Mikan Tsumiki, the Ultimate Nurse, had been absent for some time. Nagito, who had recently returned from his suspension, claimed to have seen her on the school grounds, prompting Sonia and the others to search for her while the parade was ongoing, but to no avail.

Sonia and the rest of the class later reconvened at the school classroom as they failed to locate Mikan, assuming what Nagito told them was false information. However, they were soon shocked when Chiaki returned carrying an unconscious Nagito, and Mikan, whom they had been searching for, also appeared, carrying Peko Pekoyama, the Ultimate Swordswoman, who had been injured in a battle with Junko's twin sister, Mukuro Ikusaba. Chiaki and Nagito had infiltrated Junko's lair, but before Nagito could shoot Junko, Izuru knocked him out. Chisa, who had followed them, intervened just in time to buy enough time for Chiaki to carry Nagito to safety. Although Sonia was extremely worried, especially after Nagito warned them it might be a suicide mission, she agreed to help after Chiaki reassured her. She ordered Kazuichi Soda, the Ultimate Mechanic who had a crush on her, to give the exhausted Nagito a piggyback ride so he could join their rescue party.

On their way to Junko's lair, their path was blocked by a band of Reserve Course students who wished to take them on in the battle to create placements on the Main Course for themselves. Gundham and Nekomaru Nidai, the Ultimate Team Manager, offered to hold off the attackers so Sonia and the others could go ahead. Sonia wished them luck but grew worried upon entering the underground corridor to Junko's lair. She was reassured by Kazuichi that Gundham, despite being his unofficial romantic rival, was someone who knew how to get things done, which was proven as they managed to rejoin the group thanks to Mikan's communication.

Unbeknownst to Sonia and her classmates, this path to search for Chisa was nothing but a ruse made by Junko, with the help of Mikan and Chisa themselves who had been brainwashed into despair, to lead Class 77-B into what appeared to be the same room later used for the Class Trials. In this very room, Sonia and the others were forced to watch Chiaki executed in a brutal fashion. Sonia was horrified and wanted to find a way to save her, but she couldn't tear her eyes away from the monitor. Bearing witness to Chiaki's death caused the brainwashing effect of the video to take hold of Class 77-B, plunging them into despair.

Fully brainwashed into becoming the Ultimate Despair, Sonia and her classmates received their final lesson before "graduation", the one final meeting to discuss their plan to overthrow the world with despair. Sonia swore that she would make her country "a peaceful one with no war." Chisa then activated a bomb that faked the death of Class 77-B so they could be taken off the list of protected students.

After witnessing the destruction of Hope's Peak, Sonia began spreading despair. She was later seen overseeing the destruction of an unspecified nation from within a monitoring room.

The Tragedy

Sonia joined the Ultimate Despair after falling prey to Junko's brainwashing. Alongside her corrupted classmates, she started The Tragedy and kept it ongoing even after Junko's death in the final stage of the Killing School Life. Sonia and her classmates who did not commit suicide to follow their leader Junko soon became known as the Remnants of Despair. They also hacked her body and grafted them onto themselves—though in Sonia's case, the specific body parts she took remain unknown. One of her most notorious contributions was leading an army equipped with Monokuma helmets to spread destruction and despair across the world, with Mahiru documenting the event by photographing her as she rallied her troops.

Eventually, the Future Foundation secured the custody of Sonia and the other fourteen - at first only aware that they were survivors from Hope's Peak Academy. When Makoto Naegi, a Killing School Life survivor, by that time a member of the 14th Division of the Future Foundation, realized that the survivors were in fact, Remnants of Despair, he quickly directed them to Jabberwock Island in secret.

Makoto had them enter the Neo World Program, where their memories were reset to a time before their enrollment at Hope's Peak Academy, prior to being brainwashed by Junko. As a result, none of them were able to recognize each other. The plan was to overwrite Sonia and the others' memories of themselves as Ultimate Despair, replacing them with good ones to undo all the damage Junko had done to them.

Unbeknownst to Makoto, Sonia and the other Remnants had deliberately allowed themselves to be captured. Before they entered the program, one of their members, Izuru Kamukura, the Ultimate Hope and final product of the Izuru Kamukura Project, uploaded Junko's malware AI. This AI became the virus that usurped the Observer Usami's role as teacher. Gaining full control of the program gave her the authority to convert the Neo World Program to the Killing School Trip, thereby subjecting Sonia and the others to a killing game while simultaneously using them as bait to lure Makoto and other Future Foundation members.

Killing School Trip

Once inside the realistically simulated environment of Jabberwock Island, Sonia introduced herself to Hajime Hinata, the original identity of Izuru, at the hotel restaurant. She was looking forward to the school trip, as it would be a new experience for her. She was accompanied by Teruteru Hanamura, the Ultimate Cook, who made inappropriate suggestions under the belief that princesses were groomed to lack common sense. Sonia hardly understood his perverted intention, prompting Nagito to tell him to stop multiple times.

Later, Sonia and her classmates were assembled by Usami at the first island's beach, the observer of the school trip. She reassured the students that there was no need to worry and provided Gundham and the others with swimsuits, encouraging them to fully enjoy their "school trip". Sonia accepted her offer by changing into his swimsuit and joined her classmates to enjoy the cool water.

The promising tropical school trip, however, turned into a nightmare immediately as Sonia learned that the evil animatronic bear, Monokuma, the self-proclaimed headmaster of Hope's Peak Academy, had hijacked their trip and turned it into a killing game. Sonia was shocked to see the Jabberwock Statue turned into Monobeasts, ordered by Monokuma to execute Usami-turned-Monomi into an example of participants who dared to defy his authority and killing game.

Once the killing game started, Sonia joined the morning meeting, which later became the group's daily ritual, at the hotel restaurant at the Ultimate Imposter's behest. When they appointed themselves as the group's leader, Mahiru found their forcefulness distasteful and championed Sonia as the leader instead. However, Sonia declined, explaining that her status as a princess was merely symbolic and that she would be ill-suited for the position. She held the Imposter in high regard, believing they possessed clear leadership qualities.

Sonia believed that the group should continue working together to leave the island instead of fighting after learning that everyone had their school memories stolen. To ease the anxiety caused by the first motive, she would join the girls-only dessert making gathering, which could be triggered if Hajime gave Mahiru, a certain magazine. Other than her optimism and friendliness, she also retained some of her old habits from her time at Hope's Peak, such as admiring Gundham's hamsters and ignoring Kazuichi's flirtation attempts.

Sonia agreed to attend the all-night party at the old building hosted by the Ultimate Imposter. She was excited to attend the party even though she wasn't picked to clean the party venue, which would have been her first time cleaning. Shortly before the party began, she explored the building, where she discovered the storage room she later suggested to Peko to guard one of the Imposter's duralumin cases full of dangerous items there. However, Nagito intervened and redirected Peko to the office instead. Unbeknownst to Sonia, if Peko had been stationed in the storage room, it would have foiled Nagito's plan to commit murder.

Amidst the lively party, a sudden blackout occurred. After the lights mysteriously returned, Sonia noticed and rushed to help Mikan, who had tripped into an awkward and embarrassing pose. She was also the first one to notice that the Imposter had gone missing, prompting her to search the hallway for them but to no avail. They were eventually discovered dead under one of the dining tables in the hall used as the venue, much to her shock and horror. Having waited her whole life just to have friends, Sonia initially refused to doubt any of them of killing the Imposter. However, she was eventually forced to do so to uncover the truth. She would later question the presence of the fire door in the hallway, which is commonly seen in Japanese buildings. She felt culturally ignorant for being unfamiliar with it, especially since she knew more obscure things, such as nekoyoke (猫よけ), the practice of placing plastic water bottles around a property to deter stray cats.

With the help of everyone's contributions and deductions, Sonia learned that the true culprit was Teruteru, who had attempted to kill Nagito, having blackmailed the Imposter and staged the blackout, but accidentally killed the Imposter instead, who had interfered with Nagito's plan. After Teruteru was executed, the group cornered Nagito, and Akane Owari, the Ultimate Gymnast, was moments away from punching him. Sonia stopped them, insisting everyone cease arguing on the trial grounds and instead get some rest. She encouraged them to later do their best to find a way to avoid another class trial. However, since Nagito had the chance to further harm the group, Sonia didn't protest against Nekomaru and Kazuichi's decision to tie him up later on, thinking it would be best to monitor him for a while.

Twilight Syndrome Murder Case

Following the class trial, Sonia joined the exploration of the newly opened second island. She inspected the library and discovered Jabberwock Island's guidebook which revealed that the island was artificial. Sonia also came across an occult magazine about serial killers, including Genocide Jack, the Ultimate Murderous Fiend, and her favorite, Sparkling Justice. With concerning enthusiasm, she introduced the serial killer "who only kills criminals" to Hajime and Peko, who had overheard their conversation.

The next evening, Sonia rushed to Jabberwock Park after Monokuma announced that whoever arrived first would get the chance to eat his special curry, only to be beaten by Akane. Monokuma then introduced the second motive, the Twilight Syndrome Murder Case, which Sonia ended up not engaging with. Instead, for a change of pace and to strengthen their bond, she proposed a secret girls-only party at Chandler Beach on the second island. Out of all the girls, only Mahiru and Hiyoko Saionji, the Ultimate Traditional Dancer, did not turn up at her party.

Sonia arrived a little late, just after 4 PM, at the meeting point, the diner, as she was trying on a wetsuit for the first time to prevent sunburn. She was surprised to see Kazuichi and Hajime had come uninvited. Feeling bad after Kazuichi, who had walked all the way and begged to be included, she let them join. However, when Kazuichi went ahead to prepare parasols and drinks for everyone, he discovered Mahiru's dead body inside the beach house, abruptly ending Sonia's party before it even began.

Thinking Mahiru would want her and the rest to uncover her murder, Sonia once again participated in an investigation. She immediately recognized a Sun Witch ♪ Esper Ito mask lying on the floor, the heroine of an anime that surpassed 90% viewership back in her home country, which made her excited. She quickly dashed to the library to translate information from a magazine detailing Sparkling Justice before returning to the beach house. Sonia revealed that the mask belonged to the serial killer, who always wore a heroine's mask while committing their crimes, and introduced their catchphrases to Hajime, Nagito, and Peko. Holding onto her original belief that none of her friends could have killed Mahiru, she suspected that Sparkling Justice themselves might be lurking on the island to carry out the murder.

In the class trial, the culprit was revealed to be Peko, who, much to Sonia's shock, confessed to being the Sparkling Justice. She claimed to be punishing Mahiru for covering up her late friend Sato's crime, murdering Fuyuhiko's little sister, Natsumi. Initially convinced and warning everyone about the Sparkling Justice, Sonia gradually realized, belatedly after the vote concluded, that Peko was not the real Sparkling Justice. Unlike the real vigilante, who was a Spanish native, Peko couldn't even speak the language. She had acted to hasten the vote for her and protect the real culprit, her young master, Fuyuhiko.

Peko's ruse was rendered invalid once Fuyuhiko refused to see her as a mere tool, resulting in her execution. Sonia was shocked to see Fuyuhiko attempting to intervene in her execution only to fail and suffer injuries. She immediately rushed to his side but could do nothing to stop his bleeding. Though she couldn't sleep later that night, worried about Fuyuhiko, she had no choice but to leave his fate in Monokuma’s hands as he rushed him to the hospital.

Despair Disease

In the next morning gathering, Sonia spotted an eerie memorial erected for Mahiru and was horrified. However, after learning that Hiyoko had built it sincerely, she apologized to her for not considering her feelings and even suggested that the memorial should be taken with them when they get off the island. Once the third island was opened, Sonia informed Hajime that Mikan found Fuyuhiko resting in the hospital and together with the others would visit him. Beforehand, she, following Nagito's suggestion, inspected the "Usami X File" within a laptop in the Electric Avenue containing information about The Parade. In the evening of one of the following days, Sonia joined Ibuki Mioda, the Ultimate Musician's, fireworks show while wearing a yukata in a bonus scene that can be triggered if Hajime hands Ibuki the "Summer Festivitrees" CD.

Once Fuyuhiko recovered, Sonia was surprised to see him formally greeting the group for the first time since the killing game started. She joined his recovery party hosted by Ibuki later that night, but felt the chills after watching her perform her heavy metal music. Before Ibuki could move on to the next song, Sonia was forced to rush to the First Island's beach after Monomi reported that Akane was engaged in a duel with Monokuma. She was devastated to see Nekomaru grievously injured and, like Fuyuhiko before him, taken away by Monokuma for treatment after bravely shielding Akane from her execution.

More troubles for the group came in the form of Despair Disease, the third motive of the killing game, which had different symptoms for each person and altered each contractor's personality to the opposite. Akane, Ibuki, and Nagito caught it, forcing the group to quarantine them in the hospital, with Mikan caring for them to prevent the healthy ones, like Sonia, from catching it. Sonia, alongside Hiyoko, Gundham, Chiaki, and Kazuichi, decided to station themselves at the nearby motel to support the sick students and those caring for them at the hospital in case anything happened.

While they were staying in the motel, Sonia noticed that Hiyoko refused to come out of her room until the disease was cured. Soon, Sonia realized that her reasoning was more than just that. By coincidence, Hiyoko's room was unlocked, allowing Sonia to catch a glimpse of her struggling to tie her kimono sash after showering. Hiyoko was determined to do it on her own, as Mahiru had kindly taught her the basics. Sonia then suggested she check her reflection using the full-length mirror in the storage room of the music venue.

Although Hiyoko initially kicked Sonia out, she ended up following the advice. Tragically, this led her to walk in on Mikan preparing to kill Ibuki, and Mikan murdered Hiyoko to eliminate a witness. Sonia discovered their bodies the next morning and was devastated, blaming herself for indirectly causing Hiyoko's death.

During the class trial, the group concluded that Mikan was responsible for the deaths of both Hiyoko and Ibuki, much to Sonia's disbelief. Once Mikan was executed, Sonia mourned the loss of her three friends. Still, she was relieved to learn that Nekomaru had recovered and was waiting for them on the First Island beach. Before rushing to the beach, Sonia offered a heartfelt apology to Hiyoko, Ibuki, and even Mikan for wanting to immediately give Nekomaru a warm welcome. However, her excitement quickly turned to shock, and she was rendered speechless upon seeing that Nekomaru had been drastically converted into a robot. Even though Nekomaru had already accepted his new body, Sonia was still distressed to learn that he would never be returned to his original form.

The Funhouse

Aside from adjusting to Nekomaru's new appearance, Sonia and the others grew wary of the Future Foundation and the traitor they sent to infiltrate the group, the organization Mikan claimed was responsible for transporting them to Jabberwock Island and was, therefore, their collective enemy. This was partially true, as Mikan spoke from the perspective of the Remnants of Despair. Naturally, Sonia was inclined not to explore the fourth island opened by Monomi. She further noted that exploring a new island only increased the probability of a murder to occur. Once Monokuma promised them ship parts and their Hope's Peak student profiles as a reward if they explored the fourth island, Sonia had no choice but to abide by his words. To earn the promised prize, Sonia satisfied Monokuma's request by joining everyone on the roller coaster at the amusement park, something that didn't exist in Novoselic. She had a lot of fun riding it for the first time and wanted to go again. The prize turned out to be a school file related to the Killing School Life, which, instead of helping them understand their circumstances, only confused the group further.

The group then decided to visit the Funhouse only accessible when everyone was present, to earn more prizes. The train ride to the building which Sonia found unsettling, was revealed to be a trap, as she and the others were gassed with white smoke that knocked them all unconscious. When they woke up, they found themselves inside the Funhouse's Strawberry House. It turned out Monokuma had subjected them to an escape game, where he wouldn't allow anyone to escape the Funhouse except through murder.

Instead of wallowing in their new circumstances, the group decided to explore the building using a map provided to them in search of an exit. Sonia and Gundham were the first to pair up and began exploring before Kazuichi even had a chance to ask Sonia to team up with him. Together, they discovered a lounge and traveled to the second building, the Grape House, using the contact elevator at Monokuma's behest. There, the animatronic bear revealed that he would no longer provide food or drinks, using their hunger as a time limit until a murder occurred. Rather than helplessly panicking, the group agreed to explore the Grape House in the same pairs, leading Sonia and Gundham to team up once again, ditching Kazuichi for the second time in a row.

Sonia failed to locate any exit but remained optimistic as usual. After discussing their findings, she joined the others to test Chiaki's theory about the Strawberry Tower and Grape Tower being the same building. During the test, Sonia was impressed by how Gundham's strong, trusting bond with his hamsters allowed him to command one of them to press the button that opened the Strawberry Tower door. When nighttime fell, the girls assigned themselves rooms in Grape House, with Sonia choosing one of the Deluxe Rooms. She invited Hajime to stay in one of the vacant rooms, as there weren't enough rooms in Strawberry House and he didn't get one, much to Kazuichi's dismay. Before retiring to her room, she promised to make nameplates for everyone's doors and assign their portraits.

On the third day of their confinement, Sonia and her classmates were forced to begin attending Monokuma Tai Chi sessions in the morning, intended to exhaust and starve the already low-energy students. She stayed awake that night due to hunger pangs but didn't hear the sound of Nekomaru falling to his death, as she was in the soundproof Deluxe Room. When the time to attend the Monokuma Tai Chi came, she began hallucinating Hajime as Mont Blanc and Sachertorte and Chiaki as shortcake. She was snapped out of her delusion when they discovered Nekomaru's broken body lying dead in Grape Tower. Sonia then shared the duty of guarding the body alongside Akane. Examining out-of-the-place items like the newly looking hammer and chain that blocked the door with the strawberry logo, Sonia suggested they enter the Final Dead Room but was prevented by Hajime.

During the class trial, Sonia did her best to contribute. She suggested that the tipped-over pillar was used to kill Nekomaru and that his body had been moved to explain the changing towers, though these theories were ultimately proven false. She consistently supported Gundham's arguments while ignoring Kazuichi's attempts to help. However, she eventually came to appreciate his input, though, by that point, Kazuichi had shifted to wanting to be humiliated by her instead. When suspicion fell on Gundham, Sonia asked him to explain. Once everyone's suspicion was proven correct and Gundham confessed to his crime, she refused to believe it. She was devastated by the outcome and begged Monokuma to stop Gundham's execution, but was forced to let him go at his request.

While grieving, Sonia believed they had no choice but to move forward and continue believing in each other, lest Gundham crawl his way out of hell and be very cross with them. The next evening, Sonia reflected on Gundham scolding her for begging for his life to be spared, but she believed that somehow, he would still forgive her with a smile.

The Beginning of the End

Following Gundham, who stayed true to himself until the end, Sonia was resolved not to give up on life. After attending the morning gathering, she explored the final island and investigated the military base. She found a Future Foundation document about the Jabberwock Island Development Plan in the tank's operator seat, which she assumed belonged to Monokuma, as it had been placed rather ostentatiously. It contained a lengthy redevelopment plan for the island, placing it under Future Foundation's control and preparing it as a central headquarters. She further learned that the travel agency that managed the island went bankrupt and the island became uninhabited for a long period. As a result, the island became unaffected by "the incident", allowing the Future Foundation to take control. Sonia also detected a vast amount of bombs but kept silent, fearing someone might misuse them if she told anyone. She later joined the rest to discuss their findings and the Future Foundation, in which Sonia still firmly believed that regardless the organization was their enemy or not, there never was a traitor among their ranks. That belief was challenged by Nagito, who showed up out of nowhere, announcing his plan to weed out the traitor Sonia believed never existed.

Fearing Nagito was planning to commit murder, Kazuichi devised a plan to capture Nagito, where everyone but Sonia was assigned an active role. Sonia firmly denied this and instead asked Hajime to tag along with her in the hotel lobby in thirty minutes, much to Kazuichi's dismay. What Sonia wanted to discuss with Hajime was the document she found yesterday, proposing the theory that the large administrative building the Future Foundation was referring to might have been the ancient ruins on the second island. They discovered that the door to the ancient ruins required a password to open, or could be forced open with explosives, as Sonia suggested.

Sonia joined the group to locate the bomb Nagito had planted somewhere in a place where they had never stepped. They collectively went to Nezumi Castle, where they discovered the password had been removed, which Sonia speculated to be Nagito's doing. The group began to lose hope, and Sonia tried to motivate them not to wait around until the bomb killed them, warning that it would be like the Funhouse all over again. However, Kazuichi said that only Gundham believed in that, which deeply offended Sonia. She then stormed out to continue searching for the bomb on her own.

On the morning of the deadline, Sonia apologized for snapping at the group and causing them to go their separate ways. With time running out, they were forced to split up again, and Sonia was assigned to search the smallest central island, much to her dismay. She didn't linger there long and instead moved on to the military base, where she had a plan of her own. When Hajime informed her that the bomb was discovered in the Plushie Factory, Sonia told him to go ahead and that she would catch up later.

What Sonia was planning to do instead was to confirm a suspicion she had kept to herself. Having previously discovered the existence of the bombs stored at the military base, she went there and found that the bombs were now missing, leading her to suspect that Nagito had taken them. Due to this discovery, she caught up with the others who tried to defuse the bombs in the Plushie Factory, telling them that they were fake. Her confidence came from her previous attempt at one point to use those bombs to blast open the ancient ruins' door, but she realized they were merely fireworks. While attempting this, she noticed Monomi secretly watching her. From this, Sonia also deduced that the only real bomb was the one used in the hotel lobby during the group's attempt to apprehend Nagito, which he had taken from the Final Dead Room to make his bomb scare seem legitimate.

The group was prompted to head to the warehouse following the instructions in Nagito's video message. However, they triggered a fire by opening the door, engulfing the interior. Thanks to her quick thinking, Sonia was able to direct the group to grab the fire-extinguishing supplies from the factory break room, which they simultaneously threw to douse the flames. The warehouse, now clear of smoke, revealed the horrifying state of Nagito's lifeless body.

During the class trial, Sonia and the remaining survivors worked together to uncover that Nagito had orchestrated his own death; from setting the fire, and stabbing his limbs, to impaling his abdomen with the spear he was holding. They also discovered that Nagito had died from inhaling the poisonous gas that he had put inside one of the fire grenade canisters, meaning one of the group had been manipulated into killing him without them even realizing it.

Sonia, who had suggested that the group throw the grenades, felt immense guilt and insisted that everyone vote for her as the Blackened. She was, however, blameless, as Nagito's plan was meant to force the traitor to kill him, and that traitor was none other than Chiaki, who outed herself to prevent Sonia and the others from voting for the wrong person. Sonia refused to believe Chiaki's claim to the point of feeding herself the belief that Chiaki and everyone should help her. Tired of doubting her friend, Sonia tried to stop Hajime from proving Chiaki was the traitor. Ironically, it was Sonia's own testimony about Monomi watching her discover the bombs were fake that became proof Chiaki knew beforehand they were fake, thanks to Monomi's intel. With a heavy heart, Sonia had no choice but to believe in the Chiaki who wanted to protect her and the rest, and voted for her. After Chiaki and Monomi were executed, Monokuma announced that the remaining five survivors would have the chance to graduate two days after the countdown ended.

Shortly before the countdown ended, the Neo World Program began glitching. Sonia, who had taken Gundham's Four Dark Devas of Destruction at the time, coincidentally spotted another message left behind by Nagito when she stopped by the factory. She watched the footage with everyone else in the hotel restaurant and obtained the password to the Ancient Ruins revealed by Nagito, "11037." With this knowledge, Sonia and the group hurried to the Ancient Ruins before the countdown ended. Once inside, they were transported to what appeared to be a trial ground.

Graduation Exam

Inside "Hope's Peak Academy," Sonia and the remaining survivors gathered in the gymnasium following Monokuma's announcement. He revealed that before deciding whether they wished to leave Jabberwock Island, they would undergo a "graduation exam." This exam required them to learn about the outside world by investigating materials Monokuma had scattered throughout the academy, a means meant to buy him time until "the main cast," the survivors of the Killing School Life working with the Future Foundation, arrived inside the Neo World Program. Although she did not fully comprehend their situation, Sonia stated she would do her best to gather useful clues for the upcoming "exam."

In the final class trial, Sonia struggled to accept that they had been in a virtual reality all along, existing as avatars with their school memories erased, a result she likened to a nocebo effect. She was shocked to learn that Nagito had tried to kill everyone except the traitor because he learned that they were the Remnants of Despair all along. When given the choice to either "Graduate" or "Repeat," by a fake Makoto Naegi, Sonia thought it would be better for them to stay at Jabberwock Island rather than revert to their Ultimate Despair identity. However, Alter Ego Junko—the malware that had corrupted the Hope Restoration Program into the Killing School Trip—revealed herself along with a promise to resurrect the deceased classmates. This caused Sonia to waver in her decision, tempted to choose the "Graduate" option.

Before Sonia and the others could press the Graduate Button, the real Makoto entered the Neo World Program and stopped them. In reality, if they chose to Graduate, it would allow Alter Ego Junko to upload herself into the bodies of the dead students. Makoto proposed a Forced Shutdown, a system purge to end the Neo World Program, requiring a majority of fifteen people to press "Graduate" and "Repeat" simultaneously. To activate it, Kyoko Kirigiri and Byakuya Togami, Future Foundation members and Killing School Life survivors, joined Makoto, Sonia, and the others. However, the shutdown sequence would revert the Remnants of Despair to their original state and erase all memories made during the Killing School Trip. Unwilling to lose her memories of her friends and the reason they died, Sonia began to despair, likening it to the state of "sinking into a deep, black sea."

Before Sonia could fall deeper into despair, she heard and saw a "lighthouse beacon shining across an ocean of darkness", Hajime's voice, calling out to her. Though she didn't fully understand it yet, Sonia caught a glimpse of the future they were about to create, and had already begun to create, and chose to believe in it, agreeing to shut down the Neo World Program for good.

As the Neo World Program began collapsing after Usami purged Alter Ego Junko, Sonia and the remaining survivors shared one last conversation. Sonia confessed that she was scared. But she held onto the hope that, even if they forgot what had transpired on Jabberwock Island, and even if she herself forgot, she would do everything in her might to remember. As they returned to the real world, Sonia and the other surviving former Remnants of Despair chose to remain on Jabberwock Island, possibly hoping to help their comatose friends. Kyoko speculated this decision as an indicator that they had discarded their Ultimate Despair identity.