Despite being a Fanged Beast, Kaimuu's body structure is more similar to Leviathans, specially like Tamamitsune. It has a long body covered with thick, straight sharp fur and its mouth is filled with numerous sharp teeth, besides its whiskers are very sensitive. Its clawed short legs are armored with a scaly plating.
Kaimuu prefer to live in forested areas with water resources. They like to prey on small monsters like Kelbi or even fish. Despite not being very strong, it can keep up with larger monsters thanks to its intelligence and speed.
Kaimuu has slinky, erratic movements and can attack in highly unpredictable ways: famous for outmaneuvering hunters in mid-battle and attacking them from behind. Keeping up with it while in rage mode is a challenge at best and maddening at worst. In addition to melee attacks it can hack up blobs of spit and undigested prey, inflicting the Soiled status. It can also inflict the Itchy status effect, striking hunters with the poofy, bristly hairs on its body. Afflicted hunters become covered in hairs and rapidly lose stamina to the point of being unable to sprint. What separates this from other stamina-affecting statuses is that it's contagious: if an Itchy hunter comes into contact with any of his or her teammates they'll become afflicted too!
- Its head can be damaged and its tail can be damaged and then severed.
- To get rid of the Itchy hunters must move around or roll once.