Quirks in come in many different types. But in recent chapters of the manga, it seems that there are some subtle changes to how quirks work taking place in the background. With intense emotions flying around as both the main series and My Hero Academia Vigilantes seem to be in the final stretch of their stories, it's starting to look like these strong feelings may have more of an impact on quirks than most thought.
Much of how quirks work is still a mystery to most people in this world, but the idea of quirks being influenced by the 's emotional state isn't a totally new one. The blackwhip quirk that belonged to the fifth of One for All, for example, functions at its best when the is able to harness their anger, and Re-Destro's stress quirk works similarly. Tokoyami's control of his dark shadow quirk can also be disrupted if he's experiencing extreme emotions, which is true of blackwhip as well. There are also other quirks that can influence people's emotions, such as Ms. Joke's outburst quirk. The connection between the quirks and emotional states is strong for some, but what if there's actually a connection for everyone?
In Vigilantes, the protagonist Koichi Haimawari is able to push past his limits and use his quirk in new ways on several occasions, which are consistently prompted by desperate situations and, more specifically, a friend or love interest being placed in danger. Most recently, this has manifested as an ability to leap like All Might over massive distances as he races to the hospital to protect someone. There's also the phenomenon of quirk "awakening," where someone's quirk seems to become substantially more powerful in a stressful situation. One of the most notable cases of awakening is Himiko Toga, who suddenly gains the ability to use the quirks of those she transforms into in addition to their appearance, making it massively more powerful.
While awakening a quirk is a rare phenomenon, there's nothing to indicate that only certain quirks are capable of it. Hypothetically, just about any quirk should be able to awaken under the right circumstances—it's just that the average person is never going to be good enough at using their quirk to pull it off, nor are they likely to end up in those stressful circumstances to begin with. Whether what has happened to Koichi counts as awakening is arguable, as it hasn't been specifically referred to as that in the manga, but it might be fair to say that Midoriya's ability to tap into the other quirks present in One for All is a type of awakening all its own.
A big deal has been made in recent chapters of the manga that Tomura Shigaraki's rage is necessary to All for One's body-snatching plan. It may well be possible that one of the effects of All for One on its wielder is that they begin to lose attachment to their physical body while experiencing strong negative emotions, and rather than awakening a new power, the consciousness of the previous becomes dominant instead. This parallels the way that Midoriya is able to consult the vestiges of One for All's previous s.
The idea of powering up and breaking limits in tough situations is pretty common in shonen anime and manga, but My Hero Academia's quirk awakening is certainly a unique spin on the idea. One can't help but wonder what kind of new abilities other characters might receive if they were able to awaken their quirks as well, something that's sure to provide fodder for fan speculation for years to come.
