Responses
Hmmm unfortunately the only system world hopping I know with mermaid is #16
from this list
https://www.mangago.zone/home/mangalist/2772708/?filter=&page=2
This is my world hopping / Transmigration System list and only that one has mermaid arc so far
https://www.mangago.zone/home/mangalist/2766638/
That sadly isn't the one but I am also going to reread that one 〜(꒪꒳꒪)〜
I want to reread this bl but I don't remember what it's called T-T.
I remember it is like a system one where he gets sent to different world, but the one I remember is he gets sent to a mermaid world where he is trying to prevent the humans and merpeople from fight I think and he has multiple princes/people that fall for him but he can change his appearance because he "dies" but he still hasn't completed it, but in the end he die anyway because that's how he gets out. I have no idea is that helped