Piwi: Fushigi na Ikimono

Helck is the hero that defeated one of the Demon Kings, and in the wake of the Demon King's death, a new one must be declared. This is achieved through a fighting tournament, where the strongest becomes ruler. Vamirio, one of the Great Demon Kings, discovers that Helck is a participant for the tournament and is so far winning! What could be his motive? If a human becomes the next Demon King, what does that spell for the Demon kingdom?