Nine hosts used this power in total. Keep in mind, one for all can only be transferred to the next host willingly, so that would mean all hosts had a connection to the one before some way or the other. There was s short dream Izuku had where he was able to see all of the previous owners of one for all, which means every host is informed on the fact that Izuku is the ninth holder. A short backstory, the all-powerful hero back then was All For One; he had the quirk to steal every other person’s quirk. One day he decides to give his younger brother a quirk, or to be exact, he forces a quirk on his quirkless younger brother. It was called Stockpiling, where the user was able to stockpile a ton of energy inside his body. But to everyone’s surprise, the younger brother had a quirk after all, which was the ability to pass on his quirk to other people; combining both these powers made him the first user of One For All. There started his quest to end the havoc caused by All For One but to no success. All For One, after knowing what has happened, made it his aim to kill and rid this world of all One For All users. But before the first user was defeated, he was able to transfer it to the next one. Through the research All Might has done, we were able to get whatever information we could on the previous hosts of One for All. We currently have no information on the second and the third user. The information pertaining to the fourth user is also very low; we have a brief idea of his appearance, which is just that he seems to have 2 markings on his face. Also, another fact is that All Might seems to have scribbled out all of the information he has on this user. The fifth user is Daigoro Banjo. He is the one who possessed the Blackwhip quirk combined with One For All. Izuku meets Daigoro during a battle when he blacks out; that is when Daigoro helps Izuku control the Blackwhip quirk. He passed One For All by sharing blood during a battle with All For One.
Not much information is available for the sixth user. 2 things we know, he has dark hair and wears a high collared jacket, and that he passed on One For All by a hair to the next user, Nana Shimura. The seventh user is Nana Shimura; she worked alongside Gran Torino and also helped train the next user, All Might. She was considered to be highly passionate and noble in her works; all around, she is considered as the biggest and best hero ever. Her own quirk was Float; she was sadly defeated by All For One.
The eighth user is the one the only All Might. He is, without a doubt, as we know, the strongest hero mankind has seen and is considered the Symbol of Peace.
His power and the impact he had on other people as a hero was huge, All Might, being around citizens, provided them with a feeling of safety. He was the first One For All user that was Quirkless but went on to be the only undefeated one. He was able to fight and walk out alive from All For One two times, the first time leaving All Might with an untreatable wound, which limited his use of his quirk to only three hours a day. The second time even though All Might won completely, he lost whatever power he had from One For All, leaving him retired. The ninth user is Izuku Midoriya or Deku, as we all like to call him. He was also born quirkless until All Might gave him One For All through hair. Deku seemed to have the hardest time adapting to One For All, every single time, he used the quirk; it left his body shattered. It took him a long time to get used to the power; upon training with Gran Torino, All Might, and several others, he was able to figure out ways to use the immense power without harming his body, but this can only be achieved by using a very small amount of the power. To this day, Deku hasn’t been able to master the full power of One For All. But we are sure the day is not far when we see Deku flaunting 100% of One For All and rising up as the new Symbol Of Peace.
