All For One is, quite possibly, the strongest Quirk there is in My Hero Academia. It was formerly wielded by All For One and is currently in Shigaraki Tomura's possession.
One for All is the most legendary quirk of My Hero Academia, and Deku inherited it from All Might. However, it was initially used by Yoichi Shigaraki, the series' first host, from whom it was passed down to his successors. It is an extremely strong quirk and can store a staggering amount of raw power.
Description. Original Text - (God is the quirk that everyone has, who has their own original character, quirks and entire alternate universes. The power of the quirk only has an effect on the universes that the respective user has created himself and has no influence on any other alternative universes.)
After being passed down to Izuku Midoriya, it has only gotten stronger and gained extra Quirk powers that weren't available to any previous user of One For All. It is quite easy to see that One For All is the strongest of all the powers to exist in the story.
The power of Rimuru is immense, only topped by the likes of Milim the demon lord. Rimuru is not just stronger than Deku, but even Endeavor, My Hero Academia's current Number 1 Hero, would lose to him.
During his time as the Number One Hero, All Might fought All For One twice and managed to defeat him during both encounters. Without a doubt, he's far stronger than Izuku Midoriya.
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. All For One's Quirk lets him steal Quirks from other people and use them as though they were his own.
Answer: a peculiarity of action, behavior, or personality; mannerism: He is full of strange quirks. a shift, subterfuge, or evasion; quibble.
One of the most rare quirks is any type of healing or medical related quirks. ONE character has it in the known MHA universe, which is the Recovery Girl. And the other is warp. Eri's quirk is proabably one of, if not THE most rare quirk in all of MHA.
One For All offers immense durability, and a variety of other useful abilities, but none of them are as overpowered as Overhaul. With this Quirk, all Kai has to do is touch the current wielder, and their body will be blown apart instantly, and One For All will be destroyed as well.
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.
According to Deku's mother, the inherited quirk Deku should've naturally received would've either been his father's quirk, breathing fire, or her own ability to levitate small objects.
The man that would be known as Nine was born with a Quirk that allowed him to control and manipulate the weather around him. His Quirk was immensely powerful and was viewed as a god-like ability. At the same time though, Nine was one of the many who felt outcasted in society and believed that it should not be this way.
Bakugo was stronger than Midoriya, though he indicated that Midoriya could eventually surpass him.
The fact that Endeavor's self-doubting conscience therefore tries to tear him down by saying that he'll never be like All Might, but Deku proves that Endeavor believes that Deku has already succeeded All Might.
Izuku is the last user of the One For All and also the one who goes on to become the strongest. Izuku was given this power by All Might when he was looking for a successor following the aftermath of his fight against All For One.
No. Deku's father hasn't been shown yet, but he has a fire-breathing Quirk.
After observing how the quirk reacted to the bodies of the users, all the previous wielders concluded that One For All could not be held by a user who already had a quirk. Thus, Deku is the last successor to the quirk, making him their last hope to take All For One down.