Illyria

Name: Illyria
Type: Centuries old demon (was evil, not so sure about now)
History: Illyria was one of the first demons to ever walk on the planet Earth. Millions of years ago, before humans existed and the planet was demon's paradise Illyria was god to a demon god. Her original demon form was that not unlike a snake, with several snake like limbs for a body. She had powers of altering the flow of time, talking to plants and enormous physical strength. She was killed in battle and her body was taken to the Deeper Well, where it lay for millions of years. But there was prophecy, her sarcophagus which she lay in, was to be returned to her original stomping grounds. Due to continental shift, this land was LA. With only a few of her followers still around there needed to be one in LA. That one was Knox, scientist who worked at Wolfram & Hart with Fred. Knox had chosen Fred to be the one to be the vessel for Illyria to rise again. Which Illyria did. She vowed to bring back her army and lay waste to Earth. But when she went to get her army she found that they were no more. They were dust, and she had no longer any purpose to be alive or be there.
Wesley found it in himself to take her under his wing, after she asked. Wesley couldn't say no because she had Fred's form. So Wesley tried to teach Illyria the way of the human world, but Illyria always found it hard to be in their world. A few weeks after she had been living in Fred's body her demon powers were at risk of destroying everyone. They were too much for her body to handle so a device was made to take away these powers, but let Illyria leave. It was used and she no longer had the power to alter time, but retained some physical strength.
From there on Illyria was almost part of the team. She helped on certain instances, including retrieving Gunn from a Wolfram & Hart holding dimension. She gained a friendship with Spike and lent a hand in the final battle.