Based on Guerrino's nature, the gods determined that he was not someone they needed to fight. They figured that if they entered into a contract with him, he would not hestitate to kill his fellow demons. They signed a contract, and he marched forth the take on the Shadow King's forces. He reduced them to ash as though he were dealing divine punishment straight from the heavens.
See Pactmaker Guerrino.
Artwork by Sandara.