Yuki Dharuma (Snowman)
Specialty: Water Magic
After doing the Fish Hunting with Wood in the Ice Lake, get around 450+ HP and talk to Anna in Lance about the Aurora Borealis. If you're stronge enough, she'll tell you it will come tonight. After going throught the Aurora Path, talk to the Snowman in one of the houses. After the Snowman reveal their true nature, talk to the first Snowman again, and he'll join you. The only way for him to leave the Snowman Village will be for him to get the Eternal Ice Crystal from the Ice Galaxy.
For a Magic User, Snowman has some really good constitution and defense. However, his Magic Power itself is rather low and so is his speed. He is immune to heat attacks though, so he still is very helpful. If you have him in your party in the Fire Abyss Gate, put him in Desert Lance and not much should be able to do damage to him. Supposedly, if everyone dies in the battle against the Fire Devil Lord, then Snowman will permanently sacrifice himself to kill the Guardian. Overall, if you're just looking for a pure water magician, grab Undine.