[Tilting his head left and right, Katsuki can only really judge her health by way of the, uh...human part. She definitely looks tired, that's for sure, but she also looks way too skinny to be eating right. He wants to let the poor thing sleep, but he also would like for her to eat something before she does. Thing is...Katsuki has no fucking clue what a mermaid would eat. Is it like a fish?? Does it eat the same as fish do? Algae, various other fish, sea mites, and all that other stuff? Or is it closer to a human's diet in terms of seafood?

Groaning, and rubbing a hand through his blond spikes, he crouches and watches the kid a moment with a bit of a pout. She's scared...not shit she is, it's a kid, and she's probably never seen anything like him, either.]

Naa, don't worry...not gonna hurt you. [Why would he risk his ass if he wanted to, really?] You should eat something before you sleep, Tekkamaki. Even a little bit. Can you speak?

[She clearly understands him, if the shake of her head before was any indication, so it's a good start.]