Trenkor Lep
Most Supreme Captain Trenkor Lep was a Sloathe. After nearly dying, Trenkor became an animalistic creature and one of the few creatures known to predate on Sloathes.
Trenkor was originally a captain of a Sloathe freighter. While near Aneas, Trenkor's ship captured a ship containing the Seku Leetha t'Zhan and a Promethean priest named Kimon. Trenkor attempted to interrogate the two on a Holy Book that was found on their persons before Trenkor's ship was attacked by a ship captained by Nathan li Shao while both ships were within the Ring. While Trenkor managed to kill Kimon, Leetha was able to escape hir clutches and the captain was forced to go into hiding.
To do this, Trenkor chewed a hole in the side of hir own ship. Due to the nature of Sloathe ships, this led Trenkor to gain a liking to Sloathe flesh. Trenkor then attacked Nathan and his pirate crew (killing several members of the crew) but was severly damaged when the TARDIS (flung into the System by the Charon) crashed into hir form. While this did not kill Trenkor, it led to hir becoming a nigh-animalistic creature.
While Nathan (alongside Leetha and the crew of the TARDIS) left for the wider System, Trenkor slowly floated back to Planet X through the Outer Slipstream. After landing on Planet X, the creature that was formerly Trenkor began feasting on every single Sloathe within Planet X. This was helped by the Sloathes regressing to a state of gibbering idiocy due to almost all (if not all) of their slaves being sent to Reklon. Soon, Trenkor cleared Planet X of Sloathes - even consuming the ostensible leader of the Sloathes, Pon Fuki Gek. After this, what was left of Lep grew and merged with the planet, growing ever hungrier. To stop the creature formed by this merging, Six sacrificed itself by attacking the TARDIS with hirs phobia-inducing sting. This caused the TARDIS to lash out and kill Six and destroy the thing that had been Trenkor Lep, saving the TARDIS and its occupants. (PROSE: Sky Pirates!)