Honestly I also thought maybe he is the future self but it just feels odd to me because after he shoots the guy he goes "so you reacted differently from me after all", referring to MC taking the bullet but obviously its because MC wanted to test his healing so it wasnt out of pure good will either
But anyways the idea is that if he is the future, he would be one that didnt experience the "present" in other words a form of his consciousness being pulled into the game in 2 different age groups and locations at once, so they coexist but never experienced each others lives
My other real theory is that thats not him, but his "player account", for a while now its been mentioned as a player he has Unicorn Zone as his base, and also the other guy seems to look exactly like his player account while as he is more of a younger self of his real self. So I think thats his player account that came to be from his actions but isnt entirely him
Just a guess
This is one of my fav series of the genre, and as someone who read more than halfway into the novel, well I personally dont mind "harem" or fanservice writing because in my opinion even with those elements present each female character still has a well written story that is able to make them stand out beyond the MC, and other than the female charas there are also quite a few Male characters who receive a lot of focus so its whatever to me
But for anyone curious, over time most if not all his close allies begin to find out that he is Kyle, so not only does Leo never see the girls of the present as someone his equal, now the girls also realise that he doesnt just talk like an old man but is one
The true romance elements are only ever present with Luna and Lysinas, within those 2 Luna is my personal favorite and who I think actually receives the most "love back" from Leo, but Lysinas is also a fan favorite and has quite a few scenes so, if its ever a harem I guess its not impossible it would be these 3 together. I honestly personally dont even consider any 3rd option a possibility and so far neither does Leo soooo