All For One is arguably the rarest and most powerful Quirk possessed by any villain in My Hero Academia. This Quirk so thoroughly defines its bearer that he's taken it as his name.
Izuku Midoriya's strongest Quirk is, without a doubt, the One For All. This Quirk first belonged to All For One's brother, Yoichi. After him, there have been eight more users of these powers. All Might, the eighth user of One For All, passed it down to Izuku Midoriya, making him the 9th and the final user.
Quirks are unique and memorable personality traits that make a character stand out from others. They can be physical (how they look or dress), or behavioural (acting a certain way in any given situation). They are often used to reflect a character's disposition or constant emotional state, and their tics and habits.
A character quirk is an unusual feature that sets your character apart from others. Many of the most famous figures in literature have distinctive quirks, from Harry Potter's lightning scar to Hercule Poirot's mind-blowing detective abilities.
While not every One For All user has had multiple Quirks, some of them did indeed possess more than one, with the first user of One For All, Yoichi Shigaraki, being the prime example. He has access to two Quirks, as did Hikage Shinomori, and Diagoro Banjo.
Thanks to Erasure, he can nullify the quirks of other individuals, thus turning All For One into a normal human. The one downside is that Eraserhead needs to see this target's full physical body, and his eyes must stay open in order for Erasure to remain active.
In chapter 369, he's shown crying before killing the second user, showing none of the sadism he does while killing the other users. The implication here is pretty clearly that he blames him for the death of Yoichi/his brother, who died after he passed the Quirk ontot he second user.
The seventh user of the One For All Quirk, Nana Shimura was quite a powerful woman, thanks to her receiving the Quirk from En before he died. Nana herself had the power of the Float Quirk which, as the name suggests, allowed her to levitate in mid-air.
Hellflame is the Quirk of the current Number One Hero, Endeavor. This Quirk is quite powerful as it allows Endeavor to produce and freely manipulate high-temperature flames. At its maximum power, Hellflame can prove to be lethal for almost anyone in My Hero Academia.
Explosive One for All is the best quirk in My Hero Mania without any catch. Cremation is the second-best quirk in My Hero Mania due to its strength and cool-down. In A-Tier Electrification, Explosion, and Dark Shadow are the best quirks to use.
