Psaro, the Master of Monsterkind, otherwise also known as the Manslayer, is a major antagonist in Dragon Quest IV and is both a recurring character and monster in the Dragon Quest series.He is a powerful demon, and the chief of the demon tribe and monsters, with a passionate but conflicted hatred for humanity, so much so he wished to purge them for the betterment of the world, by speeding up the reawakening of the Lord of the Underworld Estark, not realizing the true consequences of his plan, and initally putting him against the Legendary Hero and the rest of the Chosen.

Psaro returns in the spotlight as the protagonist of Dragon Quest Monsters: The Dark Prince, an expanded retelling of the events of Dragon Quest IV, but from Psaro's own perspective, narrating some events of his youth, while also telling an alternative tale were he was a Monster Wrangler in a struggle against his tyrannical father.