They appear human, but with certain feline features, like vertical slit-pupiled eyes and cat-like strength and agility. The males, like Thelo and Garris, also possess a lion-like roar. Herusans have two hearts in the right side of their chest.
A large group of Herusans arrived on the surface of the Earth in 2010, along with many other Abnormals. They were put into a camp overseen by the Lotus Defense Corps, but later seized control of it and held a number of hostages.