Commander Doom - Star Wars: The Clone Wars: Season Six

Born and raised on Kamino, Doom was a clone commander serving under Generals Tiplee and Tiplar during the Galactic Civil War. 

In 19 BBY, while fighting in the Battle of Ringo Vinda, he and the 501st Legion attempted to capture a command station operated by Admiral Trench. Engaging with Separatist forces, they were locked in an exhaustive stalemate that depleted their troops and supplies. Nevertheless they fought on, eventually capturing the post.

This advantage over Trench's forces was short lived, when clone trooper Tup broke rank and executed Tiplar. With one of his commanders dead and the leadership in disarray, Doom and his men were forced to retreat.