Fenris was a gas giant in the Manticore System, the outermost planet of the star Manticore-B.
Over 125 times the size of Earth, it orbited its primary at an average distance of 4.6 billion kilometers. It had a total of seven moons.
Its gravity well was believed to have crushed the original ninth planet of the system eons ago, turning it into the Gorgon asteroid belt. (JIR1)