Trennian is host to a massive parasitic fire demon known as T'akrin. She was essentially bred for the task of being a demonhost, then sheltered away from the world for most of her life. Around the age of eleven, she was forced to undergo a painful transformation and soulbonding ritual that tied T'akrin's essence to her and changed her body's genetic makeup and somehow managed to flee her home in the middle of the transformation.

Years later, she's a dangerous, selfish hedonist with a taste for alcohol, honey, and human flesh, the last of the three due to T'akrin limiting her choice of food to liquids or the body and bones of her former species. She's not destructive due to hate or sadistic pleasure, she's just willing to do whatever it takes to stay alive and that usually doesn't entail taking anyone else into consideration.

Despite being considered a horrifying, dangerous creature, Tren has a soft spot for cats and can be easily bribed with food. She isn't entirely the sort of companion most people want sticking around, however, as once she realizes she can get something she wants from you she will probably never leave you alone again.

Due to T'akrin, Tren is capable of spitting fire and catching parts of her body on fire, but she's only immune to heat externally. Using fire takes up a lot of energy as well, and so it tends to weaken her somewhat. Furthermore, she has a weak heart due to repeated physical trauma to the chest that occurred before she was exposed to T'akrin, and as a result cannot fly long distances and has heart trouble sporadically.