Chapter 217

A New Power and All For One is the two hundred seventeenth chapter of Kohei Horikoshi's My Hero Academia.

Synopsis
Around 7:00 PM at evening, Izuku and Katsuki engage in a sparring match at Gym Gamma. Katsuki questions Izuku on why he hasn't activated his Blackwhip ability, in which the latter reveals that it apparently can't be unlocked as of now. All Might immediately tells the two to halt the match for the sake of discussing more about Izuku's current development. As the brief brawl stops, Katsuki points out that Izuku's black tendrils only appear whenever he's put into mortal danger. All Might then expresses concern for his pupil, Izuku.

A flashback reveals the three discussing Blackwhip and the One For All predecessor who possessed it. Katsuki asks All Might how he knew about the black tendrils, but All Might admits that he too was in the dark about it until Izuku filled him in. All Might wonders about the bald predecessor and the fact that One For All is capable of letting Izuku use previous wielders' Quirk, saying that his master, Nana Shimura, probably didn't know that this was a possibility either. Katsuki asks Izuku if there was a trigger that caused Blackwhip to manifest, but the latter denies this, explaining that he was only told that ‘the time has come' and wondering if there could've been some form of external catalyst. Katsuki then asks if this turn of events has anything to do with All For One, explaining that it would make sense as he was the person who created One For All in the first place and he can also possess multiple Quirks.

The flashback ends and Izuku wonders if it is truly All For One's power that caused Blackwhip to appear.

Izuku and Katsuki re-enter the dormitories for the former to find Tetsutetsu shouting about the differences between Hardening and Steel to a defeated Eijiro. As Tetsutetsu says they both have different strengths, Tenya runs past, announcing that dinner is beef stew. Izuku realizes that Class 1-B has joined Class 1-A at their dorms, and walks further in to see the two classes happily socializing in the common area.

Shoto approaches Izuku, asking if he also has two Quirks and if he was still hiding his power when he asked Shoto to come at him with all he had, to which Izuku hurriedly replies that the black tendrils might be an extension of his original Quirk, and he wasn't holding back against him. Shoto believes him, and Katsuki cringes over how dense he is for someone so sharp. Izuku compliments Shoto on how much flame he was able to generate in the battle, but Shoto denies this, saying that he hasn't changed at all compared to Izuku. It is revealed that he requested that his father, teach him about one of his fire moves.

The next day, Present Mic, Shota and the rest of the U.A. High School teachers are shown discussing Hitoshi Shinso's graduation to the Hero Department. They decide that it will definitely be happening.

As Present Mic and Shota leave the meeting, Present Mic compares Hitoshi to Shota in his younger years, going on to ask if he is going to "do this again", and mentioning "Shiragumo". Shota requests that if he wants to say something he should keep it short, as Shota has somewhere to be.

Eri, Izuku, Mirio and Neito are standing outside the teaching staff dormitories, the former saying the latter is U.A.'s dark side as he points at her and loudly asks what she's saying. Mirio says he taught Eri that Neito is the dark side of U.A. during the Cultural Festival, and Izuku asks what's going on. Shota then approaches them, apologizing to Izuku and Mirio for calling them out so suddenly, explaining that he wanted Neito to help with something but didn't want to leave him alone with Eri as his eccentric personality would be bad for her mental health.

Inside the building, Neito attempts to copy Eri's Rewind Quirk. He grows the horn that is required for its usage, but says that he is incapable of using the Quirk itself and apologizes for this to Shota, who says it's unfortunate. Mirio and Izuku question what's going on and why Neito couldn't use Copy on Eri's Quirk, and Neito explains that as Rewind is an accumulation-type Quirk like One For All, it isn't possible for him to use it. He states that his Quirk allows him to copy the fundamental abilities of a Quirk, not something requiring stored-up energy as he cannot copy what has already been stored. Izuku is relieved that he has this mechanism as it prevented him from being damaged by One For All when he copied during the Joint Training Battle.

Mirio asks why Neito tried to copy Eri's Quirk in the first place, and Shota explains that as Eri doesn't understand how to properly use her power, Neito copying it and learning it would help her and make it easier for her to learn it as well. Eri apologizes for causing everyone trouble, saying everyone would be better off if she didn't have her ability, but Izuku reminds her that it was her power that saved him, stating that what she said is not true at all. He explains that what power is worth is all about how it's used, comparing it to how a knife is dangerous initially, but when used right can make all kinds of food, and saying that her power is an amazing one.

Izuku says that he'll try his best after all, and promises himself that he'll master One For All.

Chapter Notes

 * This chapter serves an epilogue and concludes the Joint Training Arc.
 * All Might allows Izuku to train with Katsuki in order to learn more about the Quirks contained within One For All.
 * Katsuki notes that this development might be due to All For One's influence.
 * Shoto contacts Endeavor on how to improve his overall abilities by learning a new Super Move.
 * Present Mic reveals that he and Shota once had an old acquaintance known as Shiragumo at some point in the past.
 * Neito reveals that Eri's Quirk can't be copied since its accumulation-type like that of Izuku.