I think in general, they don't care very much about human customs or anything. All they care about is protecting the sea. They kind of have to relearn all human customs again, so they might watch humans a lot or ask older seiren and other ocean folk about it.
If they used to be calm people, they would generally still be calm. If they were always angry and violent, they will be angry and violent when it comes to defending the ocean. xD
If they used to be calm people, they would generally still be calm. If they were always angry and violent, they will be angry and violent when it comes to defending the ocean. xD