Cat Seal
A seal type creature with mediocre stats. It's an all-rounder with a variety of potential skills for different situations, but the fact they have Push and Dive as fixed skills means they'll usually play a supporting role. They very rarely show up in wandering enemy groups spawned from walkable water tiles, and can be captured like any other creature.
Not really worth going out of your way to acquire unless you want to get to SealHaven, but there is a special one you can acquire by starting a new game and only taking highlighted professions and traits for your MC. This specific Cat Seal will have the special traits Starter, which allows it to increase its Max Level, and Lucky, which gives you an extra choice in Essence Portals.
There is also an event that can trigger while Dating Lumira on the beach that shows more art for the Cat Seal.