In the Super Famicom version, Goowain is one of the names for a recruited Slime Knight. A Slime Knight can be recruited if one of the party is a Rank 2 Monster Master.
In the DS remake, Goowain can be recruited as soon as the magic key is obtained. He is beyond the magic key door in Prince Howard's room. Speak to him and he will ask to join the party.
Living up to his name, Goowain is gallant, noble, and honorable. As a Slime Knight, he rides a large green-colored slime (his 'gloopy steed') and wears grey armor. His shield has a slime carved into it.
Goowain is met at level 1.
Goowain learns a number of skills on his own, regardless of vocation.