kinda incest? in anime/manga

i be reading jujutsu kaisen ya know? pretty fucking baller of a manga but then mei mei (the girl with the white braid covering like half her face) be spawning out her lil bro. but like the lil bro thinks of mei mei like she can shit golden eggs. shit also happened in ouran highschool host club which i mean, they do be kinda cute but nasty too.