Sunao Sumeragi

Sunao is known for her extremely hot-headed nature and admits that once she loses her temper, she completely loses the ability to think rationally.

During her harsh training period at Tsuzura Temple, her impulsive behavior led to a record of being sent to the reflection room 82 times, earning her the infamous nickname "Sunao of Komiya."

After suffering a humiliating defeat against Kazuya Kagami, however, she became deeply ashamed of her actions.

Her personality has since softened considerably, though she still doesn't hesitate to deliver a merciless iron fist to Kazuya if he accidentally sees her naked.

She is a classic tsundere who gradually develops romantic feelings for her rival, to the point of secretly keeping his photo in her wallet.

Once, while sharing a futon with him, she accidentally blurted out her true feelings, though Kazuya remains convinced it was just an act.

Sunao originally fulfilled her Susoharai duties in Komiya, a region neighboring Kamioka that houses the Sumeragi family estate.

After a threat loomed over Kukuri's life, she was dispatched to Kamioka as a temporary support for Kazuya by the order of Takamagahara.

Because of this, she moved into the Kagami household and transferred into Class 2-4 at Kamioka East Middle School.

She also officially joined the school's "Worry Consultation Room" group.

When Sunao was a child, her beloved older brother, Suou Sumeragi, was killed by a Kaii.

Driven by curiosity, Kanaka Kagami had crossed regional borders to see the creature and ended up defeating it herself.

This caused Sunao's anger to take a leap in logic, and she branded Kanaka as "the enemy of my enemy," vowing revenge.

When she finally confronted Kanaka, however, she was completely outmatched.

They made a pact: Sunao would train hard, grow stronger, and then return for a proper duel.

Kanaka even trained her personally before she left to undergo rigorous training at Tsuzura Temple.

Tragically, by the time Sunao returned from her long training, Kanaka had already passed away.

Learning that Kazuya, whom she saw as weak and unreliable, had become Kanaka's successor as Kamioka's new Susoharai infuriated her.

She ambushed him on the school grounds, punched him immediately, and accused him of being unworthy of succeeding Kanaka.

She then challenged him to a duel.

A week later, Kazuya managed to awaken a powerful new ability and defeated her soundly.

Kotetsu & "Kamigakari"

Initially, Sunao treated Kotetsu, the bladed Tsugumono once wielded by her late brother, as a mere tool.

After her duel with Kazuya shattered Kotetsu's hilt, she finally offered a heartfelt apology and expressed her genuine wish to stay together.

This trust allowed Kotetsu to regain his human form and enabled Sunao to achieve "Kamigakari," a supreme unified state.

The power she displayed was remarkable, reaching the level of Nine Seals, a tier that surpasses the known maximum of Eight Seals.

Despite this feat, she hasn't received an official recommendation for promotion, so her formal rank remains at Seven Seals.

Kazuya Kagami

Sunao's rival turned love interest.

She initially despised him as a weakling unworthy of his position, but his true strength and his sincere bond with his Tsugumomo won her over.

Although she has fallen for him, she still reacts with violent jealousy whenever he gets close to other girls.

Her Family

Sunao's mother, Suzuri Sumeragi, has a strict and fiery personality.

After Sunao lost her duel and broke Kotetsu—a taboo for the undefeated Ogi school—her mother threatened to expel her from the family.

As a condition for forgiveness, she ordered Sunao to either kill Kazuya or make him her fiancé.

The resulting scheme, which involved inviting Kazuya home for a disastrous act, ended in failure and a severe punishment from her furious mother.

However, since the expulsion was never finalized, the engagement technically remains in effect.

Her father, Susumu Sumeragi, married into the family and, like his daughter, is completely dominated by his wife.

He is an extreme doting parent who views Kazuya with open hostility.

Sunao's late brother, Suou Sumeragi, was Kotetsu's previous partner and lost his life in a battle against a powerful Amasogi.

Later, Kiriha reveals to Sunao directly that she was the one who killed Kanaka Kagami.