11 || Shouta Aizawa

a hero that can't save them-self isn't able to save anyone that’s his mindset after Oboro died

Aizawa's reaction to Oboro's death was profound grief, leading him to become a more solitary "underground" hero and to develop the personal philosophy that a hero who can't save themselves can't save anyone. He initially reacted with shock and sorrow, especially after discovering his friend's corpse had been turned into the Nomu Kurogiri, which he expressed through tears and shouting at the villain to try to reach his friend. His immediate grief manifested in his reluctance to deal with emotions, causing him to shut down and avoid discussing Oboro even with Hizashi Yamada (Present Mic).
Initial shock and grief: Aizawa was deeply saddened by Oboro's death, and was devastated upon discovering the truth about Kurogiri. He was visibly overcome with emotion, with tears streaming down his face as he yelled at Kurogiri, pleading with him to remember their dream of becoming heroes together.
Mental and emotional shutdown: He dealt with his grief by shutting down emotionally, a trait that continues years later. This led him to avoid the topic, and he sometimes reacted harshly to Present Mic when he tried to bring it up, as shown in this Reddit discussion.
Shift in hero philosophy: Oboro's death cemented a core belief in Aizawa: "a hero that can't save them-self isn't able to save anyone". This traumatic experience pushed him to pursue a solo career as an "underground" hero, relying on his own skills rather than relying on a team in the same way he had with his friends.
Strained friendships: The emotional toll of Oboro's death caused a rift between Aizawa and Present Mic, with Aizawa distancing himself for years.

After his death Aizawa decides on his future, this traumatic experience imprinted into him the ideal that would stay with him his whole life, a hero that can't save them-self isn't able to save anyone. It is this mentality that propelled him to pursue a solo hero career relying on only himself to accomplish his goal.

Personality
Stern and logical: He has high expectations and is very blunt, often coming off as cold or apathetic.
Caring: Despite his stern exterior, he is deeply invested in his students' welfare and pushes them to their limits to help them become stronger heroes.
Lazy: He often appears lazy and is frequently seen sleeping in his sleeping bag, but this is a strategic way to conserve energy.
Strategic and intelligent: His intelligence and cleverness make him a formidable opponent and a brilliant instructor, often seen using his knowledge to outsmart foes.

Quirk: Erasure
Ability: When his eyes are open, he can instantly nullify the quirk of anyone he looks at.
Limitations: He must keep his eyes open to use it, which leads to him wearing goggles to hide his line of sight from villains and causes dry eye.
Catch: It does not nullify the effects of a quirk that has already been used or one that has been stored, and it does not affect mutated or non-humanoid quirks.