Venus Blood -Ragnarok-

Prince Vaari is a descendent of Overlord Loki who, 500 years ago (in Venus Blood Frontier), subjugated the 5 warrior goddesses of Yggdrasil and founded the kingdom of Asgard. Under Loki's rule the demon and divine races were united in tenuous peace. But Loki went missing, and for a time the vassal goddess Odin ruled in his stead. Odin finally passed away, and a movement favoring those of divine blood seized power. Vaari, then a child, was driven from the capital due to his strong demonic blood, while his half-sister Brunhilde with strong divine blood was taken under their wing.
Years later, as conflict between the demon and divine races erupts into civil war, Vaari encounters an arrogant young boy who calls himself Loki and bears knowledge and a sharp wit that belie his appearance. The boy promises Vaari great power--the power to subdue and enslave the newly-awakened warrior goddesses--if Vaari can fight his away to the Divine Tree, claim its power, and prove his mettle. Chased by Brunhilde, who now wields the power of the holy relic Nibelung, Vaari sets out to unite the squabbling races of Asgard once again under a new Overlord.