When Demon Queen Echidna begins her invasion of the human realm, the people turn to the hero Leo Demonheart to protect them. Blessed with insurmountable power, Leo easily repels Echidna's army, thereby saving the world. But instead of gratitude or admiration, Leo is met with disdain and scorn from his fellow humans, who fear his overwhelming strength and believe that it may eventually cause humanity's demise.
Banished from the kingdom he once called home, Leo wanders aimlessly throughout the land until, one day, he hears rumors of Echidna's efforts to rebuild her army. Hoping that demonkind might accept him as an ally, he returns to the demon queen's castle and offers Echidna his help.
Naturally, Echidna immediately rejects him. Still, not all hope is lost, as Leo manages to convince Echidna's four generals to let him secretly work under their supervision. Donning the identity of a masked dark knight named Onyx, Leo solves the demon army's problems one by one—gradually improving the quality of life around the castle. Above all else, however, Leo wants to accomplish one goal: to learn why Echidna started the war in the first place.+ More
Recommended for you
Fumiko's Confession
ONA
2m
Green Legend Ran
OVA
45m
Fist of the Blue Sky
TV
27m
Astarotte's Toy EX
OVA
21m
Time Bokan Series: Yatterman
TV
22m
Time Stranger
Movie
88m
Stratos 4
TV
23m
Wild Arms
TV
24m
Yu-Gi-Oh! VRAINS
TV
24m
Dino Mech Gaiking
TV
24m
The Devil Lady
TV
25m
