The League of Villains

Motivation. Most often, it's a mixture of resentment, disappointment with the hero system, and a desire to prove his worth. Sometimes, he's specifically recruited by the League or All For One, seeing enormous potential in him.
Personality. In different versions, he's either a cold and calculating strategist who retains his analytical mind, or an emotionally broken man who lashes out at those around him. However, glimmers of the former "good" Izuku often remain—for example, he might spare one of his old friends.
Abilities. There are different options here:
A quirkless Deku who relies solely on his intellect, training, and equipment.
Deku has One For All, but he uses it brutally and to the limit, without caring about his own body.
Deku, who received a quirk from All For One or even became the heir to that power himself.
Role in the League. He is often portrayed as a "dark reflection" of Tomura Shigaraki: if Shigaraki is the embodiment of destruction, then Deku is destruction spiced with insight into how heroes work from the inside. He can be a tactician, a field commander, or a "special threat" deployed against the strongest heroes.
Appearance. This is usually a more sinister image: dark clothing, gloves, sometimes red eyes or visible signs of injury, emphasizing the fact that he constantly overexerts his body.
Deku knows the hero system from the inside, so as a villain he is especially dangerous: he can attack the weak points of the academy, teachers, and other students.

Giran
Role: Criminal broker, not a permanent member of the League, but works closely with it.
Activities: Helps the League find new recruits, organizes deals and covers operations.
Character: pragmatic, cynical, acts solely for profit, but is reliable as a business partner.

Dr. Kyudai Garaki (Daruma Ujiko)
Role: League scientist, creator of Nomu.
Traits: Not a fighter, but one of the most dangerous members of the League due to his research. His work modifying humans and creating Nomu makes the League much stronger.
Motives: Obsessed with the idea of ​​"perfection" through quirks and willing to make any ethical compromises for the sake of his experiments.

Mustard
Role: Support, crowd control specialist.
Quirk: Creates sleeping gas.
Weakness: The gas affects him too, so he has to use a gas mask and time it.
Character: nervous, cautious, tries to stay in the shadows and complete tasks without unnecessary risk.

Magne (Henji Hikishi)
Role: melee fighter, part of the strike team.
Quirk: Magnetism - Can attract/repel metal objects and even people with metal implants or accessories.
Character: straightforward, aggressive, prefers to act rather than reason.

Mr. Compress (Atsuhiro Sako)
Role: Abduction and transportation specialist.
Quirk: Compresses objects (and people) into small balls that can be carried.
Personality: Theatrical, loves dramatic gestures and phrases, and often behaves like a showman. Despite his villainy, he possesses a unique sense of honor and loyalty to his team.

Spinner (Shuichi Iguchi)
Role: street fighter, symbol of protest against discrimination against those with “unaesthetic” quirks.
Quirk: Reptilian abilities - clinging to walls, growing in mass, releasing scales.
Appearance: lizard-like features, rough clothing that emphasizes his "street" identity.
Personality: Stubborn, principled, believes society is unfair to those whose quirks are considered "scary" or "strange." Later, he becomes one of the ideologists of radical views within the League.

Twice (Jin Bubaigawara)
Role: Tactician and support, creates copies for reconnaissance and distraction.
Quirk: "Doppelganger" - Can create autonomous copies of himself and other people.
Personality: He suffers from dissociative experiences: he has difficulty distinguishing the original from the copy, which causes severe anxiety. He tries to be helpful and friendly, although his abilities intensify his feelings of loneliness.
Peculiarity: His mask and style are an attempt to hide his insecurity and create a “stable” identity.

Himiko Toga
Role: League scout and saboteur.
Quirk: "Metamorphosis" - after consuming a person's blood, he can take on their appearance.
Appearance: Petite, light, tousled hair, large eyes, often with a wide, almost crazy smile; wears a school uniform in her own style.
Personality: Chaotic, emotionally unstable, but very observant. She perceives violence and transformation as a way to "get closer" to those she likes. Her image combines childlike spontaneity with a frightening obsession.

Dabi (Tōya Todoroki)
Role: One of the key fighters of the League, a symbol of personal revenge.
Quirk: Blue flames, much hotter than normal fire.
Appearance: Tall, thin, skin covered in scars and burns due to his own quirk; black hair.
Personality: Cynical, sarcastic, obsessed with ruining his father's (Prospector's) reputation. His motivation is to show the world the cruelty of a system that demands heroes be "perfect."

Kurogiri
Role: Shigaraki's deputy, the League's "logistics center."
Origin: An artificially created Nomu from the body of Oboro Shirakumo (a former U.A. student). Created by Dr. Garaki at the behest of All For One to protect Tomura.
Quirk: Warp Gate - Creates a dark fog that allows you to teleport people over distances.
Personality: Calm and level-headed, he acts as the voice of reason in the League. Unlike other villains, he's more cool-headed and pragmatic.

Tomura Shigaraki
Role: The de facto leader of the League after being strengthened, Midoriya's main rival.
Quirk: "Disintegration" - Anything he touches with his five fingers disintegrates. Later gains the power of "All For One."
Appearance: Pale skin, arms positioned haphazardly on his body (a symbol of his trauma and obsession with "getting rid of everything unnecessary"), often in torn clothing.
Personality: Unstable, filled with anger and disgust for society. His tragedy was the uncontrollable onset of his Quirk, which led to his accidental murder of his family. This made him obsessed with the idea of ​​destroying the "normal" world.