What I think is that he became a kid because he was "reborn/revived" so he became a kid and will grow up once more but as a vampire this time. But idk if what I'm saying is true just a theory.
LOLL totally get u my dear In case if u wanna read sth complex too bt with a clear happy ending, try complex - manda ringo Its a bit old but truly phenomenal. Its really realistic too, in case if u like those stuff
The only difference is that the seme doesn't have a child. Can someone tell me the title plsssss
Following because I somehow because remember it too but I don’t know the name
http://www.mangago.zone/read-manga/sensei_wa_butchozura_shite_yatte_kuru
Maybe this one?
Commenting to come back later.... and also cuz I don't remember the name either