I recent just started to read the MHA manga(only on chap. 18)
I have ran across spoilers for the manga from chap. 184 and up and let me tell you, my guess this entire has been correct.
Bokugou has always seen Izuku’s self-destructive tendencies since they were literally children, when he was still a quirkless little nerd and I think even back then, with him going through his own superiority complex, it scared him to see Izuku act like that.
And it was even more obvious and confirmed when Izuku was quick to run and try to save him during the slime/sludge villain when they were 14. Because just think about it: izuku, who is pretty much quirkless and powerless, was fast to be the first one to step in and at least try to save Him.
You can tell in Katsuki’s eyes, even through the fear of what was happening, was shocked by the action. He was shocked that Izuku genuinely looks so terrified for him- of losing him, despite all the possible situations of Katsuki being a complete ass and bully towards him as they watched each other grow up- one gaining more confidence and selfish views while the other feeling weak and worth nothing.
It’s a great concept to think about and I think I want to finished reading the manga until I am caught up before I jump back into the anime because these two lives are so intertwined no matter if people like it or not.
I like to think about how Bokugou really did try to distance himself for Izuku at some point during UA BC he couldn’t think or accept the fact that the nerdy, not-so quirkless anymore , childhood friend of his was willing to risk his life over and over again just to be able to save, save, save. That’s never really broken down or spoken about just yet but I think it should be pointed out. And it’s just interesting to see how much Bokugou truly actually cares about Izuku and his well-being and probably has this entire time, despite all that he has said and done.
