they were children kept in an island stolen by a cult(?) they each have different powers and marks on their bodies, pretty sure the mcs mark was like a spiral shell (its on the cover), theres a time skip to after they escaped the island, some were adopted and they kinda hate each other/want to forget the past, the mc is bullied in school and is the only one that likes being together with everyone
as for the other children:
girl twin is super strong na-hui??
guy twin is a loser
blue hair guy was adopted by a rich family
tall guy has a third eye
one never grew/has a pet duck
one died
fire girl
something like one-sided hate to one-sided crush ml?
https://www.mangago.me/read-manga/the_s_classes_that_i_raised/
Here's the manhwa link :)
bl with good plot and interesting, not too toxic ml, minimal papapa, and plot other than romance
I cant stop thinking about dreadful night ;;-;;
#17-23, 27-32, 48, 50, 52-60, 62-67...
https://www.mangago.me/home/mangalist/476814/?filter=&page=2
I think there is an R-15 version and a mature version that you can choose from for this one: https://www.mangago.me/read-manga/bongchon_bride/
And sorry, I know you’re looking for manhwa, but this one is too good not to recommend! https://www.mangago.me/read-manga/yoake_no_uta/

any stories with these tropes?
-playboy gets pinned down
-scholars bickering/bickering power couple
-one of the leads arent over ex
I read this a long time ago, but if I remember correctly, bottom is not over ex.
https://www.mangago.me/read-manga/bitter_minami_haruka/
https://www.mangago.me/read-manga/aesthetics_of_unpleasantness/
uke's a classic frat fuckboy, seme and uke have crazy good chemistry, and they bicker a lot throughout the first two seasons, when they break up, both of them aren't over each other, but reconcile really nicely in season three.
it's a whole rollercoaster of emotions, and i really like it :D