In order to adapt to a world overrun by plants, humans inserted biological factors from animals into their bodies, awakening the wild, savage nature within. As a result, they lead lives more close to nature than that of the Hourai. Because the original creatures they drew from range from the cowardly to the savage, their ecology heavily varies, but because their base is that of a human, their intellectual level typically isn't very low and many of them have fairly mild personality.
Lycanthrope with various biological factors such as wolf, bear, cat, rabbit, and so on have been confirmed, but individuals with multiple biological factors have not been discovered yet. The herbivores oppose the constantly flourishing plants, while the carnivores oppose the Plasect and several of the Leafer.