Indomitable Will

It doesn't matter if I stand a chance or not! I have to fight you here and now! Who is gonna fight if all the heroes run away?

Indomitable Will is the ability that belongs to characters who possess exceptionally strong willpower.

Overview
The user has unnaturally strong willpower, enabling them to endure great physical pain and psychological trauma. Indomitable Will grants the user an extreme amount of perseverance, making them refuse to surrender no matter how many difficulties they may face, and possibly even allows the user to remove their limiter, becoming even stronger than ever. Through their will, the user can push past limitations and stay active longer than usual, though depending on the strength of the user, it may depict how long they will last until their body gives up on them like Mumen Rider.

Trivia

 * It is possible that Saitama's willpower is one of the factors in attaining his unparalleled strength, as according to Dr. Genus, Saitama has removed his limiter through sheer effort despite having no particular talent.