戦勇。 is a Japanese manga series written and illustrated by Haruhara Robinson. It was first published as web manga in Niconico Seiga in August 2010 and because of it's popularity, it was serialized in Jump Square since June 2012. It was also adapted into an anime television series in 2013.
Long ago, there lived an evil being who reigned over the world through fear, called Satan Rchimedes. He invaded the human world with his many demon underlings, spreading madness and chaos everywhere. One thousand years ago, this menace was sealed by the hero Creation, and peace returned to the world. However, a gigantic hole suddenly opened up in the world one day, and demons appeared. The king thinks that this portends the return of the demon king Rchimedes and The king decreed that the descendants of the hero must take on the threat, and 75 people showed up. Hero No. 45 (Alba) and a sadistic palace warrior (Ros) team up, and their adventure begins.
