
I think Kiyo is not immortal. Maybe he's like the homunculus in fma where he has a few lives

Maybe it’s because he’s eaten part of a mermaid, his life is lengthened and he heals faster, but that is not immortality. Eventually it will wear off and he will die. He’s even aging, because he only eats a little bit of it too. His mer-husband looks like a child when he turned into a human, and looks significantly younger when he’s in his normal form, despite being way older. He is immortal, not the human. Kiyo just lives for a long time and heals from serious injuries quickly, that it feels immortal. ?? That’s my best guess.

Nothing to say to the commentators except that yall are entitled as fck. Like i know i'm using this site too but at least you should respect these fantranslators wishes and not trash them for it. If you don't agree with them then just don't read their works lol. Yall be the same person who'd make the fantranslators fed up and drop their projects, and then beg them to pick up the projects again
Yes king call him out on his shit