Humans are a recurring race throughout the Dragon Quest series. In almost every Dragon Quest game, the hero is human or at least partially human, and in many cases the entire party is composed of humans. The only non-human heroes are the Hero from Dragon Quest IV, who is half-Zenithian, and the Hero from Dragon Quest VIII, who is half-Dragovian and the Hero from Dragon Quest IX who is a Celestrian. The party is exclusively human in the original Dragon Quest, Dragon Quest II, Dragon Quest III. Some of the games suggest that Erdrick and his descendants are somehow more than Human, but it's never specified exactly what makes them capable of performing feats other Humans cannot.
This should not be confused with Humanoid monsters.