They mention mermaids, and a knight jokes about her being one.
Later they mention that foreign queen eating mermaids, and she's also looking for ice magic users.
Are ice magic users descendants of mermaids?
Also the mom said she was taken from a box, so it's possible the dad was a noble or even royalty from that other country, and he rescued a captive mermaid who was the mom.
Who knows, but they've mentioned mermaids twice now and the mom mentioned the sea so I assume mermaids are super plot relevant or something.