Regressor as a side character? Umm, there's quite a few :>
OOOH I WANT ONE I WANT ONE !!, mind giving me a few sauce?
These are pretty famous ones, I think you've probably read them. I can only name a little because my memory fails me lol:
Omniscient Reader's Viewpoint
Regressor Instructional Manual
Preference for the Possessor
... Sorry that's all I remember at the moment so sorry
OMG WAIT I SHOULDVE KNOWN i forgot orv existed
NO BECAUSE OMG SAME
HAHSHAHAAHHAJAHAHAJAA IF YOU GUYS EVER REMEMBER MORE, SHARE PLEASE
i swear there was a manwha, like the main character had a regressor sister?, or the main character had a sister who transmigrated into their world AHHH I JS CANT REMEMEBRRR
OMG I KNOW THAT WAIT A SECOND
I'M THE MAIN CHARACTER'S LITTLE SISTER
Her brother consists of a transmigrator, regressor, and a reincarnator, respectively lmao
TYY WHAT
There's also The Civil Servant Hunter’s S-Class Resignation Log
Where the side characters include a regressor and a returnee.
Omggg yeahh, that one's good too! Oh, I also remember this manhwa about someone awakened as a housekeeper class, her brother is a gardener, and she's scouted by the strongest awakened lol
The Housekeeper in The Dungeon! I had to search the title cause I forgot. I also found this reddit, save it for future references lmao https://www.reddit.com/r/manhwa/s/qVikKsKNWe
OMG WAIT I remember I remember, there was a historical MANWHAAA the MC was a girl and her sister too obvi. So like, both of the were transmigrators, except one of them, went back to the past, and another reincarnated into them. Please tell me if you remember the title!! ><
The MC is....something. LOVE the premise. Like omg where have u ever seen a manhwa put a regressor as A SIDE CHARACTER?? I love flawed characters don't get me wrong,, but man the way she acted for the first few chapters. I get it, yeah, relatable character on top of being OP, doesn't want people to find out that, traumatic backstory, yadayada, but she just didn't give ykno. Complaining and not helping during that first rift scene and then on top of that, seeing her acting all bratty in Dohyun's house... quite literally plummets my first impression of her. She wasn't relatable in any sense,, she just seemed like a spoiled brat in the first few chapters. And the pacing of this story does not help our girl at all. The story only ever picks up at what,, chapter 9?? She didn't bring anything to the table for the first few chapters. I literally did not have anything looking forward to or wondering 'what's gonna happen now?' regarding her, our MC, in the beginning of the story-- and that's crazy story writing.