So far, the war is just a way to get any competition out of his way. I don't know if it has any in universe explanation, but having seen how Selebus handles things like this, I wouldn't doubt the chance of it being explored to some degree. If I had to guess, assuming there is a canon explanation, the war is a measure the gods took to avoid other people getting in the way, other guys in particular, so Sensei could mess with the girls unimpeded by other guys. Any other guy that exists is, so far, unable to get in the way even without the war or is likely a war casualty. Examples of this include Geoffrey, who is Ayane's butler, and Ayane's father, who is apparently a very busy man with no time to do anything with the girls.What the 'Space War' is might be an interesting story. We seem to have this little bubble dimension which seems to be designed for Sensei in which we have this weird ass war that makes absolutely no sense whatsoever and no one questions it. This seems to be because they are all controlled in some way. (At one point, Makoto realises that having two annual beach trips in one year obviously doesn't make any sense but then gets forcibly reset to not have ever thought it, no one else even seems to consider this even though it should be obvious) What the Space War is, is an intentionally dumb excuse for why no other guys are around to be competition for Sensei as he parades around and grooms a bunch of girls in a world made for him.
Without looking in universe, however, it is just a reason that there are no other guys in the game so as to avoid a certain three letter fetish that just so happens to be notorious on F95 for starting thread wars.
He is, to some degree, aware of the resets as he has been affected by past resets about the same as Maya, which is to say not at all. That said, his awareness may change in the future now that we know even Maya can be affected. If she can be reset, so can he.i have a question if you don't mind answering, do you think Sensei is somehow aware about the reset stuff and about the "angels" and "god" or "hope" and also about his body being used like an "avatar" for the player?