Dabi

What happened between them?
Endeavor had Toya with one goal: to surpass All Might. He raised him hoping he would become the hero he himself could never be.
Toya inherited extremely powerful flames, even hotter than Endeavor's, but she also inherited a resistance to cold from her mother. Her body did not tolerate her own fire well.
When Endeavor discovered that Toya was not suitable to become his successor, he stopped training him and focused his expectations on Shoto.
Toya felt rejected and replaced. He felt as though his father had stopped seeing him as a son and only valued him for his potential.
Despite being forbidden from using his flames, Toya continued to train obsessively to prove to Endeavor that he could surpass All Might.
Finally, the Sekoto Peak fire occurred, where everyone believed that Toya had died.
Toya survived, but was severely burned. He then adopted the identity of Dabi and developed a deep desire to destroy Endeavor's reputation and life.

Hair: Dark, originally black, although it is often seen as very dark blue, spiky and messy.
Eyes: Turquoise/light blue, with a cold and intimidating gaze.
Skin: Much of his body is covered in burned skin and scars.
Scars: He has extensive areas of burned skin, especially around his jaw, neck, chest, arms, and legs.
Staples: His wounds are held together by numerous metal staples, which are part of his characteristic appearance.
Face: His face shows visible burns and a usually serious or disturbing expression.
Build: He is tall, thin and quite athletic, although he does not have as much muscle mass as Endeavor.
Clothing: He usually wears dark clothing, especially a black shirt/pants, along with a dark-colored coat or jacket.

Cremation (Blueflame): His Quirk allows him to generate extremely hot blue flames, capable of exceeding the temperature of normal fire.
Great destructive power: It can launch enormous flames and concentrate them to attack from a distance, burning or destroying large areas.
Flame Control: He can produce fire from different parts of his body and use it to create wide or concentrated attacks.
Ranged combat: His style is mainly based on keeping the enemy away and bombarding him with fire.
Pain resistance: Despite his severe injuries and burns, Dabi can continue fighting even under extreme pain.
Tactical ingenuity: He is quite cunning and knows how to take advantage of the environment and the weaknesses of his enemies.
Knowledge of Endeavor: As Toya Todoroki, he has a deep understanding of Endeavor's techniques and abilities, giving him a tactical advantage.
⚠️ Their biggest weakness
His body isn't adapted to withstand his own fire. Although his flames are even hotter than Endeavor's, Dabi has a much lower heat resistance. That's why the longer he uses his Quirk, the more damage his body sustains.