lol i like how Ayto randomly pops up at critical moments all the damn time and suddenly he's a pro at whatever the situation is needed. you need a doctor? you got it. you need a fighter? you got it
Feels like the protagonist has some bad memory lapses in his childhood. It seems to be implied that Ayato was actually the childhood friend and not Yuugaku. As for Yuuki and Nagumo, not real sure about that.