Catavolcus

Catavolcus was a warlord who once fought the Doctor. (DWM: The Neutron Knights) He also attacked Gallifrey some time before its first destruction in the Second War in Heaven against The Enemy. (PROSE: The Gallifrey Chronicles) In an alternate universe, the Time Lords knew it was a threat they were destined to survive. (PROSE: The Infinity Doctors)