Soga Kugisaki

Soga Kugizaki is an ally to Knuckleduster and a former Impromptu Villain.

Appearance
Soga is tall and skinny young man with spiky hair, clenched teeth, and slanted eyes. He wears a tank top with a sleeveless vest over it, jeans, leather shoes, and a plaid shirt tied around the waist. His front teeth are shown to be sharpened to the point, while his back teeth are regular molars.

Personality
Soga has a cruel and violent personality, and likes to humiliate and attack people. This stems from the fact that he has been discriminated against due to his actions and his Quirk. He seems to think that everyone around him sees him as some sort of monster, and has developed a love of making other people suffer in place of him due to these circumstances.

He shows some signs of mental instability, as shown when he sees everyone around him with a mocking, condescending smile, and laughing at him, no matter who they are and what they are actually doing, suggesting he is unable to separate reality from his perception of the world. It is suggested that this perception of the world is what makes him so violent.

In spite of these flaws, he shows solidarity with his friends, who are other people who have been looked down upon due to their Quirks. He shows a strong sense of loyalty and cares towards them, such as when he went to face Kuin alone and warned her to leave his friends out of their conflict. He also is very defiant when he knows he is being played, totally trashing a selection of Trigger drugs because he refused to aid in Kuin's plan in any way.

Synopsis
Koichi Haimawari unwittingly bumps into Soga and spills Soga's juice. Wanting to humiliate Koichi, Soga asks him to apologize and kneel, but Koichi flees. After that, he and his friends enter a convenience store, and they encounter Koichi again. Soga becomes angry at seeing Koichi again and takes him outside to beat him. Koichi is not able to fight back because of Soga's spikes. Later that same day, Koichi and Pop☆Step meet the thugs in an alleyway, and the thugs recognize her as the online idol and begin mocking her. Haimawari tries to stop them but gets beaten again.

Suddenly, Knuckleduster appears and defeats them with ease. Soga rises again and threatens to hurt Pop☆Step's face, but Koichi charges at him and knocks him down, allowing Pop☆Step to fly above for safety. Knuckleduster punches the thug leader into the wall which knocks him out. After that, the thugs are offered samples of Trigger from Mario Kugutsu.

The next day, after seeing Koichi and Pop☆Step chasing Mario, Soga uses the Trigger sample and attacks Koichi. Soga is captured and arrested by Shota Aizawa, who is on his day off.

He is later attacked by Stendhal and is narrowly saved by Koichi and Knuckleduster.

Quirk
Spike: Soga can create spikes from his body, initially only being able to do so from his hands and feet. When he is under the effect of Trigger, spikes grow all over his back, head, and arms and he throws himself spinning at his enemies. Later, when his life is endangered due to Stendhal he manages to take on a full-body transformation, growing taller and altering his face to become lizard-like - additionally, he grew spikes in the same places that he previously had under the effects of Trigger.

Trivia

 * His name contains the kanji for "nail" (釘), "peninsula/spit" (崎), and "animal claws and fangs" (爪牙).