Cell Activation

Rendered in Japanese as 細胞活性 and read Saibō Kassei, Cell Activation appears in My Hero Academia: Heroes: Rising. Three people are tied to it: Katsuma Shimano, his father, and Nine, who tore it out of the elder Shimano's possession. It is classed as an Emitter Quirk operating strictly at contact range.

It also holds a small distinction in franchise history. Among the powers taken by an All For One wielder, this is the first named Quirk audiences watch being stolen on screen.

Touch is the trigger. Skin contact lets the wielder switch on the cells inside a body, their own or somebody else's, and drive that activity upward. Recovery accelerates sharply, wounds close faster than they should, and physical condition can improve past where it started.

The limits are real. Running the power drains the user's own stamina, and holding it going for a stretch leaves them worn out. Blood type acts as a lock, with some people simply incompatible, though Katsuma's version appears to sidestep that restriction. Nothing happens at a distance either, since contact must be maintained throughout, and the process is unhurried rather than instant.

Katsuma Shimano can rouse and accelerate cellular activity in anyone he lays hands on, and the film implies he can turn it inward as well. After Izuku Midoriya and Katsuki Bakugo lose their first clash with Nine, Katsuma works on both of them, mending their injuries, shortening their recovery, and sharpening their performance. Holding contact that long leaves him spent. His reach covers Type O and Type A, and Nine confirms Type B works too.

Katsuma's father handles the same trick on himself or others, closing wounds and speeding recovery, but he states his own version only functions on people with Type A blood.

Nine takes the ability from the elder Shimano using All For One, then hits a wall. His own Type B blood is incompatible with the version he stole, so the power he wanted for himself refuses to work on him.