Senkou no Flash

Name: Senkou no Flash (Flashy Flash)

Alias: Hero of Light Speed, “Forelock Germa” (nickname given by Saitama)

Gender: Male

Age: 25

Height: 172 cm

Weight: 65 kg

Affiliation: Hero Association

Hero Rank: S-Class Rank 13

Weapon: Sword “Instant Kill Maru” (originally; later replaced after being broken)

Occupation: Professional Hero, former assassin of the Ninja Village

First Appearance: S-Class emergency summons during Dark Matter Thieves incident

Voice Actor (anime): Kosuke Toriumi

Senkou no Flash is an S-Class hero who relies on overwhelming speed, precision swordplay, and assassin techniques to annihilate monsters before they realize they have been attacked.

Despite being only 13th in the S-Class ranking, his pure combat power is described as top-tier, on par with Bang, Atomic Samurai, and Chougoukin Kurobikari, and he can defeat certain Dragon-level monsters depending on compatibility.

He is nicknamed the “Hero of Light Speed” for his incredible mobility and instantaneous lethal strikes.

In battle, he often ends fights so quickly that observers can barely follow his movements, if at all.

Flash is outwardly cold, stoic, and almost always expressionless, a direct result of being raised as an assassin in the brutal environment of the Ninja Village.

He rarely smiles, keeps his emotions tightly controlled, and tends to speak in a confident, sometimes cutting tone.

He has a very strong sense of pride in his combat ability and especially in his speed.

He claims he has never boasted about his speed “like some side character would,” though he admits people often say that his fights end very quickly.

Flash holds a serious professional attitude toward being a hero, even lecturing Saitama on what he thinks a proper hero should be.

He sometimes refers to himself as the “protagonist,” reflecting his high self-regard and childlike stubbornness when it comes to admitting defeat.

When Saitama casually surpasses his speed or ignores his challenges, Flash is heavily shaken but refuses to acknowledge that he lost.

Similarly, when Blast effortlessly dodges his maximum-speed attack, Flash is shocked to the core.

He has a short temper and can get heated quickly.

He nearly attacks Sweet Mask during a verbal argument and shows little hesitation in killing monsters the moment he encounters them.

At the same time, his dedication to training is extreme; he insists he became strong simply because he trained harder than anyone else.

Beneath his cold demeanor, he is capable of attachment and respect, and with Onsoku no Sonic in particular he once showed a rare genuine smile.

Original Webcomic Design

In the original ONE webcomic, Flash has medium-length hair that reaches about his shoulders and long bangs that fall near his eyes.

He wears a simple outfit resembling a collarless shirt and pants, along with a cape, giving him a slightly minimalist, assassin-like look.

Murata Remake Design

In the Murata-drawn remake, his design is more elaborate and androgynous.

He has long hair extending down his back, styled with a decorative hairpin that resembles a light effect, and he also wears a brooch.

His outfit is a tight black bodysuit similar to Onsoku no Sonic’s, paired with metal armor on the shoulders and chest.

He wears slim high-heeled boots, enhancing his slender and elegant silhouette, while still conveying the image of a lethal professional killer.

Flash specializes in ultra-high-speed combat, combining assassin techniques, precise swordsmanship, and acrobatic kicks.

His movements are so fast that even skilled fighters like the A-Class ninja hero Shadow Ring cannot track him with their eyes.

His speed and technique allow him to instantly reduce enemies to pieces, and he is considered one of the Hero Association’s “superhumans,” alongside fighters like Bang, Chougoukin Kurobikari, and others of similar caliber.

He once defeated two Dragon-level monsters simultaneously, demonstrating that in a pure battle scenario he is among the absolute top within S-Class.

Unlike Atomic Samurai, whose power drops drastically without a sword, Flash can still fight effectively with hand-to-hand combat techniques.

In the original webcomic, Awakened Garou remarks that Flash “would have been dangerous back when I was still human,” acknowledging his threat level.

In the remake, Flash fights both a still-growing Awakened Garou and Black Sperm in close combat, managing to hold his own for a time despite being outclassed.

He shows notable durability as well, withstanding attacks from both Black Sperm’s evolved forms and Awakened Garou.

Flash’s fighting pride is extreme: he confidently asks Terrible Tornado if she really thinks she is stronger than him, indicating how highly he rates his own abilities.

Even after being clearly surpassed by Saitama, he clings to his pride and refuses to accept the reality of the power gap.

Flash’s style revolves around instant acceleration, rapid direction changes, and chaining lethal strikes from sword and kicks.

Below are his main known techniques, as described across the original and remake versions:

Signature Sword Techniques

Flash Slash (Senkou Zan / Flashy Slash)

A high-speed sword technique in which Flash blitzes his target and cuts them to pieces in an instant.

He used this move to simultaneously bisect Gale Wind and Hellfire Flame, both high-level ninja opponents.

Heavy Flash Slash

A focused thrust-like attack with his sword that concentrates power on a single point.

In the story, he uses it mainly for weapon breaking rather than cutting flesh.

Retsukuu San-Sen Slash

A technique learned from “That Person’s” secret manual.

By swinging his sword, Flash creates a thin tornado that slices through enemies, capable of annihilating Dragon-level monsters in an instant.

Kicking and Mobility Techniques

Wind Blade Kick

A spinning kick performed while rotating his body, often generating intense cutting force through the air.

Onsoku no Sonic uses a technique with the same name, highlighting their shared ninja lineage.

Dragon Thrust Kick

A straight downward thrusting kick, with his leg extended like a spear aimed at the target.

It combines speed with piercing power.

Flash Kick (Senkou Kyaku / Flashy Kicks)

A series of high-speed kicks, either as a rapid-fire barrage or as a single devastating strike.

The sheer number of hits in a fraction of a second makes them extremely difficult to block or evade.

Wave Surge Wind Blade Kick

Another technique learned from “That Person’s” secret manual.

Unlike the normal Wind Blade Kick, this attack doesn’t rely on direct impact; instead, it creates a massive slicing wind, like a large, invisible blade of air.

Movement and Feint Techniques

Flowing Shadow Leg

A high-speed movement art where Flash dashes so quickly that he leaves numerous afterimages.

Onsoku no Sonic can manage about ten afterimages with his own ultimate technique, but Flash’s afterimage count far exceeds that, demonstrating the gap in their speed.

Top Spin Slide

Flash rotates his body while sliding along the ground, allowing him to change direction and evade while maintaining speed.

This movement can be used defensively or as a setup for counterattacks.

Mist Wrap

He throws his cape over an enemy to blind their vision and restrict their awareness.

This tactic plays into his assassin background, using distraction and blind spots to create openings.

Hand Techniques

Flash Fist (Senkou Ken / Flashy Fist)

Used during his fight with Garou.

Flash closed the distance within 0.01 seconds and, by 0.02 seconds, had already landed 18 consecutive strikes.

Falling Leaves Barrage

A flurry of palm strikes or slaps delivered at high speed.

The name evokes the image of countless falling leaves, emphasizing the sheer number of hits.

Clear Storm Fist

A rapid, single-arm barrage of blows.

With one arm, Flash unleashes a concentrated storm of punches too quick for ordinary opponents to react to.

Meteor Palm

A large, powerful double-handed palm strike.

This attack trades rapid hits for a single heavy blow, like a meteor crashing down.

Flash initially meets Saitama during the Monster Association raid while clearing monsters in their underground base.

He mistakenly assumes Saitama is a monster and launches a surprise attack, using his ultimate Flash Slash.

To his shock, Saitama casually reads and avoids the move.

Unsure whether this was a coincidence or proof of overwhelming superiority, Flash agonizes over it and attacks again, only for Saitama to pinch his sword mid-swing and then label him a “monster” with the nickname “Forelock Germa” based on his bangs.

Later, when the underground base collapses due to Terrible Tornado’s telekinetic assault, Flash and his sword Instant Kill Maru become trapped under rubble.

Saitama happens to be nearby, and Flash persuades him to dig him out.

Flash’s priority, however, is saving his sword rather than his own body, forcing Saitama to help in a way that annoys him.

When Saitama angrily reacts and accidentally bumps him, Instant Kill Maru ends up broken anyway, leading to a comedic but bitter loss for Flash.

After the Monster Association incident, Flash recognizes that Saitama’s physical ability is extraordinary.

He attempts to recruit Saitama as his disciple so he can “teach him the secrets of combat,” completely failing to understand that Saitama exists on a far higher level.

When they have a sparring match so Flash can “educate” Saitama, Flash discovers that his speed is absolutely ineffective.

Saitama dodges everything without effort, yet Flash remains stubborn and refuses to admit clear defeat.

Despite this pride, Flash gradually becomes more involved with Saitama, eventually claiming Saitama as his own disciple in front of others.

When Onsoku no Sonic later declares that Saitama is his primary target and that Flash is second on his hit list, Saitama casually states that Flash is his disciple and that Sonic can only fight him after defeating Flash, redefining their rivalry in an amusing way.

Flash and Onsoku no Sonic are both products of the Ninja Village and are deeply connected by their shared past.

They are classmates from the “End of the 44th Class,” a generation with an infamous reputation.

Flash was sold into the Ninja Village at age five.

There, the children were subjected to inhuman training: “one day equals 72 hours,” with only six hours of allowed sleep, and even suicide was forbidden.

He was branded with harsh punishments whenever he attempted to escape, and the scars from those days remain on his body.

Under these conditions, the Ninja Village raised children as assassins, and Flash’s batch would later be remembered for its catastrophic outcome.

To destroy this evil system, Flash deliberately pretended to be a failure.

By acting like a dropout, he ensured he would be pushed into the harshest possible training, sharpening his skills beyond any ordinary curriculum.

During this time, he met Onsoku no Sonic, who was an actual dropout, not pretending.

In a place where casual conversation was prohibited, Sonic’s attempts to talk to him became a vital lifeline for Flash’s mental stability.

They began acting together, secretly practicing higher-level techniques behind their instructors’ backs.

Their bond grew through shared training and whispered conversations, quietly defying their oppressive environment.

During a survival exercise in the forest, Sonic confided his dream to Flash.

He wanted to destroy the current system of the Ninja Village and turn it into a place where orphans could learn how to live freely instead of being turned into killers.

Sonic invited Flash to join him in this dream, saying that Flash had the same kind of eyes as someone who wanted to change the world.

Flash, driven by his own notion of justice, listened and continued to sharpen his skills in silence.

Eventually, the day of the graduation exam arrived.

By then, the instructors had already seen through Flash’s act and ranked him first, fully aware of his tremendous potential.

This did not matter to him.

On the day of the exam, he decided to fulfill the justice he had nurtured since childhood and enacted his plan.

Flash massacred everyone associated with the Ninja Village: instructors, administrators, and classmates.

The incident effectively annihilated the Ninja Village from within and would later become known as the “End of the 44th Class Incident.”

Flash then left the ruins of the village behind and eventually joined the newly formed Hero Association.

He repurposed his a