Can you please give a breakdown on Chisaki Kai's quirk Overhaul? Like any possible theories on how this quirk works, etc. ?
So I’m definitely not a physics person. I’ll be real and say I don’t quite know what exactly you’re looking for when asking this question, but I’ll do what I can here with some of my spare observations regarding Overhaul the quirk and the character, and I’ll let you run with them if you like.
Horikoshi seems way more invested in the effects of this quirk to use in his story rather than the actual logic behind how it could work. I don’t know what anyone else has said on the topic, but this is certainly not my area of expertise.
The interesting part of his quirk is the time lag between disassembly and reassembly. There seems to be no mention of concern regarding Chisaki’s knowledge of anatomy. He seems to be able to just do what he wants to molecules at will without any knowledge of molecular science. He can disassemble a person (objects too) and put them back together, alive and well and even healed. Honestly, that doesn’t make much sense, so I can see why you’d be curious about it.
The other interesting part is how he mentions anything he puts back together isn’t quite the same as it was before. It also appears to be an unpleasant experience for the reassembled person. I don’t know what this means from a physical standpoint, but it illustrates Chisaki’s callous Machiavellian bent and sadistic edge.
He does seem limited by the types of molecules at play. He can combine two objects but he can’t turn one object into something completely different. In a way, his quirk reminds me of the limitations of alchemy in Fullmetal Alchemist, but there’s a lot more gray area with the Overhaul quirk.
The real question would be about his quirk factor. Without his hands, which seem to be the only focal point of activation, does his quirk factor still exist? Could All For One be used to steal the Overhaul quirk from him as he is now? Could the molecules in his body be rearranged to restore his arms at the cost of something else like say his feet? If that’s the case, it’s very possible we haven’t seen the end of the Overhaul quirk. Hell, even without that kind of interference, a quirk awakening on Chisaki’s part could result in him being able to activate it with another part of his body, maybe.
Horikoshi makes a point of tying quirks in to the users’ personalities, which I think in this case is mostly about Chisaki seeing a world he wishes to reshape to his liking. He refers to people as sick and claims he has the cure, but then his cure should leave the person “not quite the same as before.” He doesn’t really care about what’s lost in the process of achieving his cure. And of course he displays massive hypocrisy in showing no interest to cure his own quirk. He also represents a clear parallel to AFO, given both have such an obsession with bringing order to society where they both stand at the top.
But ironically, I do actually think he is right about quirks, at least as presented in the arc and future plot points; there is a heavy implication that quirks need to be eradicated from the human race or else humans are likely to destroy themselves. I really wonder about the theory presented in the Overhaul arc (manga only) that states quirks arose from a virus carried by mice (Principal Nedzu, anyone?) To recreate humanity without quirks, rendering them “cured” but “not quite the same” seems right in this wheelhouse. I wonder about the repercussions of such an outcome, given how I’ve pointed out how people’s identities are so tied to their quirks. This would be my greatest interest in the Overhaul arc as it relates to the greater MHA story.
Anyways, those are my general, disorganized thoughts on Overhaul.