From Creatures Wikia
The Traitor Grendels are a genetic breed by anaisa. They prefer to slap grendels more than norns. They were released for the CCSF 09.
Baby-child: Young traitor grendels are nervous creatures that run away from other grendels from the moment that they're born. They have to because if they stayed with their parents, they'd probably be smacked to death. As all traitor grendels are, these are friendly towards norns and ettins. However, if there are other traitor grendels around, large groups of norns will probably have one or two. A traitor grendel's childhood is a very lonely one.
Adolescent: The only age in which they're likely to breed, adolescent traitor grendels are friendly most of the time. They don't attack other grendels or run away, which also means that they're the most likely to be smacked to death in traitor grendel society. They are friendly with norns and ettins.
Youth-Ancient: The traitor grendels finally show their true colors and start attacking other grendels. They don't even spare fellow traitor grendels, hence why babies and children are so nervous. They can still breed, but are very unlikely to. They are territorial and will guard their norn/norns against any grendels. They are hosted at ds village.