Movies made surviving a zombie apocalypse out to be a lot easier than it was. In the movies, they at least gave the main character someone to tough it out with. Kuroo was alone, running and avoiding any combat until he managed to find an abandoned pharmacy. What the movies didn't make clear or stress, though, was the rush he got when he saw the first regular human in four days.

He wasn't sure when it happened. All he remembered about the sudden change in view was that it was definite. Midoriya might have seen heroes as something to look up to, but that was the past. They were just people that were born lucky and lived lucky lives. Maybe the solid realization is what lead him to agree and join the League of Villains. Maybe it was gradual, or all at once.