Psaro

Psaro, also known as Psaro the Manslayer, is the main villain and one of the most important figures in the world of Dragon Quest IV. He is a demon that passionately hates humans and ever since he lost his lover to them, holds a lethal grudge against them.

Appearance
Psaro at first appears fairly humanoid, though his red eyes, pointed ears, and vast powers would no sooner reveal him for what he really is. He has long silver hair and wears a dark outfit with a single distinct shoulder pad, spiked and appearing to be made of bone, and a long fur cape. Upon using the Secret of Evolution he turns into a brown look-alike of Estark who loses his arms and head as the combat progresses to steadily morph into a green horned vicious monster with a second face on his torso.

History
Psaro hates and is in turn reviled by humans, revered by demons and the inhabitants of Rosehill. When Rose, his lover, was attacked by humans for the ruby tears she sheds as an elf, he protected her by concealing her in a small fortress he built far away from human settlements. The town of Rosehill grew up around it as others looking for shelter from humans relocated there. Psaro paid frequent visits to Rosehill in order to see Rose; he told her of his plans to destroy humanity to free the world for demons, and continued on with righteousness in spite of her pleas to stop and try for coexistence.

Towards the end of the game, Rose is murdered, causing Psaro to go insane. He loses what little inhibition Rose had given him and uses the Secret of Evolution to transform into a monster, destroying his personality as an unavoidable side-effect. The only thing he remembers is his desire to destroy humanity. In the end, he is defeated by the "Chosen Ones".

In the DS version, after the main story is complete, an alternate choice can be made in which the hero/heroine can seek out a mystical flower from the holy tree Yggdrasil that can be used once to bring back the dead; the hero/heroine can use it to bring back Psaro's beloved Rose. The hero can then escort her to Psaro's domain where she can restore Psaro to his senses and make him return to normal. After this Psaro will show regret for his actions and gratitude to the human heroes for saving his lover, he will then join them on their crusade to destroy the true villain of the story, the one responsible for Rose's death and Psaro's corruption, Aamon.

Trivia

 * His appearance, behavior and motives are reminiscent of Sephiroth, a villain from the veteran Square  RPG series,  Final Fantasy . They are often portrayed together in unofficial fanworks, mainly in Japan.
 * In Dragon Quest Monsters Joker 2 he can be obtained thorugh synthesis of a Roseguardin and Ruin, he appears in his monster form.