Go Crazy! You Call This a Beast Master

This is a world where the beast master is respected. All battles depend on the pet beast contracted by the beastmaster. But Keiji, who came from time-travel, is an alien. He has the super bug that perfectly replicates the ability of pet beasts and surpasses the limit. After he contracted with his natal fantasy beast, he began a legendary life of tearing apart war beasts with his hands. His fighting style subverted the world's cognition and shattered the world's outlook. Keiji: "I'm just an ordinary beast master!" Legendary beast master: "Are you crazy! You call this a beast master!"