Water people

Water People are a mysterious race of liquid creatures. They used to exist in the Plane of Water, but were driven out when Enigmas invaded their realm. This caused them to be flung across all kinds of planes, and those who ended up in the Plane of Darkness created Akvavit Castle.

The language that they speak is the Erimu Language (Aquarium in the fan translation). It's written in a gibberish blend of hiragana and katakana, and sentences end with a bubbling noise. The only way to understand what they're saying is by having Blueberry in your party, as she is fluent in Erimu.