Kario es un chico que toda su vida fue marginado porque era un poco raro no controlaba su fuerza era muy rapido y parecia que leia mentes pero lo que nadie sabia era que es un demonio Oscuro un demonio que lo echaron magia negra al nacer su padre el rey de los demonios Oscuros lo habia abandonado en la tierra por que lo aburrio mucho tener que cuidarle aunque el mayor trabajo lo hacian sus esclavos Kario en forma de venganza fabrico un anillo que lo concedia transformarse en monstruos diferentes y después lo mato y se convirtio en el rey de los demonios oscuros todos esos demonios tienen la tradicion de echarse magia negra para vendecirse ante el dios del infierno el dios Hades.

Ralph's free translation:

Kario is a boy whose whole life was marginalized because he was a bit weird he did not control his strength was very fast and it seemed that he read minds but what nobody knew was that he is a demon Dark a demon who cast black magic when his father was born King of the Dark demons had abandoned him on earth because he was so bored having to take care of him even though the biggest work was done by his Kario slaves in the form of revenge, he made a ring that allowed him to transform into different monsters and then killed him and became the king of the dark demons all those demons have the tradition of casting black magic to sell themselves before the god of hell god Hades.