This isn’t a bad theory, but there are a couple of questions about this. Like if the MC is in fact the reincarnation of Adrest then why do we have a vision of the past? Like during zone zero where the MC has a vision of the past when they, Aelita and Ren come across the house at hiyoshi pass? I played as Axel and he had a vision regarding himself and Ariana with Axel playing a prank on Ari. So I don’t know if it’s so much the MC is the reincarnation of Adrest, but rather they are two souls that share the same body, or all the main protagonists souls have fused into one body along with Adrest. This is just me though. Not disagreeing with your theory, just a few questions on it.