I played these years ago and I don't entirely remember it cause it was during the 2020 quarantine haze, but the protagonist was a flippant guy (maybe hooded?) that seemed to warp into worlds (timelines? dimensions? i think just like different worlds) and on each one he basically found, corrupted and trained a girl into (presumably) joining his harem. Each game wasn't too long, he acquired a girl per game, and I think I only played two games. I remember one girl was like a timid girl with dark hair and the other one was a stubborn upper-class blonde girl (a princess or knight?). The second world was more medieval-style and the first one I don't remember well, it might have been medieval, old Japanese or modern. The protagonist himself had more sci-fi style gadgets if I remember correctly. The guy was noticeable taller than the girls and the vibe of the game was corruption and maledom.
The animated 2D sprites were high quality and I'm pretty sure they were pixel art. Perspective wasn't isometric or topdown but side-view, though it wasn't a platform game, I don't even remember if it qualified as a very basic RPG. I'm not sure if it was made in the RPGMaker engine, but if it was it definitely wasn't using default graphics and as I said the perspective wasn't topdown.
In case this info helps: I'm not sure but I think the same dev had another game with very similar aesthetics which was isometric/topdown (with some perspective shift during sex scenes) but I didn't care much for because it felt a bit femdom-y and more softcore. It had two girls (one quite young) and one guy, and the whole sexual progression was more slow burn (I remember most of the game taking place in a house and its outskirts, and a lot of softcore stuff in a bed like grinding and whatnot).