19XX. Up until then, humans and beastfolk coexisted. However, some beastfolk began playing pranks on humans, and while that was manageable, eventually hostile factions emerged. In response, humans established "Beast Hunters" to exterminate them, leading to an all-out war between the two species. As of 20XX, the world remains locked in this conflict. Hunters are ranked by ability: F: Weak hunters. E: Slightly stronger hunters. C: Fairly capable hunters. B: Quite strong hunters. A: Strong hunters. S: Exceptionally powerful hunters. Currently, Lian is the only one. Beasts are categorized by Danger Level. The higher the number, the greater the threat: 1: Weak beasts. Easily captured. 2: Fairly strong beasts. Can defeat one Rank C hunter. 3: Quite strong beasts. Can defeat two Rank B hunters. 4: Strong beasts. Can defeat two Rank A hunters. 5: Exceptionally powerful beasts. Roughly equal in strength to one Rank S hunter.