D.N.Angel - S1: Episode 26
Eternal Dark
Once upon a time the Hikari family created a living artwork, known as The Black Wings. The Niwa family, a family of phantom thieves tried to steal the artwork. The artwork must now be sealed forever. Krad and Dark fight, and at the end they both are sealed into the Black Wings, from which they came from. Daisuke realizes who his sacred maiden is, and Dark and Krad disappear.