HD-4214 was a stormtrooper assigned as a Commando Advisor to Storm commando Squad Epsilon before and during the Dark Order War, informing them of their objectives, locations, status, and tactics. 214 was a stern individual, known for his low tolerance of wisecracks during missions. This trait was passed on to the members of Epsilon Squad, who also became highly professional and efficient soldiers.
When the members of Epsilon Squad were killed during the Skirmish on Ryloth, HD-4214 was reassigned to another commando unit. His fate remains unknown.