What kind of Quirk is One for All?
All Might and Izuku’s legendary ability belongs to a rare subtype called Accumulation, in which a user can store power to release at a later time. One for All allows Izuku to gain and wield the Quirks of other people, including its previous users.
Other Accumulation-type Quirks include Fat Gum’s Fat Absorption and Rikiya Yotsubashi’s ability to turn stress and frustration into raw power.
How do people develop their own Quirks?
The exact cause and nature of Quirks are unknown. Nearly 80% of children develop their powers at the age of four, inheriting or combining the Quirks of both parents like in the case of Half-Cold, Half-Hot. The presence of only one joint in a child’s pinky toe is seen as a sign that the child will develop a Quirk.
Children may take longer to manifest a Quirk; those who fail to do so when they reach adolescence are looked down upon and labeled Quirkless, like Izuku Midoriya.
Which character has the strongest Quirk?
There are many contenders for the user of the strongest Quirk.
In terms of pure destructive power, Shigaraki Tomura’s Decay is clearly one of the strongest as it disintegrates anything he touches.
For Quirks with great technical applications, Erasure lets Shota Aizawa temporarily erase Quirks through eye contact, and Bloodcurdle allows Stain to directly paralyze opponents.
Shoto Todoroki simply has a versatile array of potent fire and ice skills.
But pound-for-pound, the strongest Quirks go to the twin powers of All for One and One for All, which grants their users Quirks from other people and lets them synergize these to devastating effect.