So, looking for an mc that goes from ancient to modern, instead of the typical going back in time. Basically, anything apart from Harem and an actually ancient person, not someone who goes back and forth. Nothing under 100 or so chs pls. Thanks!
I am afraid you won't find many with that kind combination (I mean all of those that I know do have harem in them so I can only recommend one which doesn't have that many in it as far as I know): Strongest Abandoned Son
There was/is a manga/manhua/manhwa about martial artists getting summoned into modern time via a failed experiment ... but sadly I just cannot recall the name of it ...
Returning from the Immortal World It started of directly on the return so modern time. When I last read it (around 700 chapters in), they were still in modern world and no immediate signs of going back to Ancient Times (ie Immortal World).
That's too specific my friend, while the idea is interesting even if you find such webnovels they're guaranteed to be crap. Usually you need to have about 100 webnovels of some genre for one of them to be great or at least decent. No harem narrows it down further towards the realms of impossibility and while I'm not a fan of harem either, you better suck it up coz they fking dominate webnovels and fanfics, and you're gonna miss out on some awesome stories for some content you can simply ignore. I recommend Super Minion on RRL, not what you asked but the MC's reaction is similar. MC is a biomachine weapon without knowledge of the outside world so it's reactions to everything are always entertaining. That reminds me, some super heroes come from low level civilizations like Thor (kind of, they've got some powerful stuff but are backwards nonetheless) so you could search in that area of fanfics.