Ennen, also known as IC-4447, was a clone commando who served in Galaar Squad. During the Clone Wars, he was trained under the Cuy'val Dar program by a Corellian sergeant for the Grand Army of the Republic.
After the implementation of Order 66 and the subsequent rise of the Galactic Empire under Palpatine, Galaar Squad was dissolved. Ennen, together with his squadmate Bry, joined Omega Squad's members Niner and Darman Skirata to create Squad 40 within the 501st Legion. Their first mission as a newly formed squad involved going to the planet of Celen to capture Jilam Kester, an Antarian Ranger aiding Jedi in escaping the Empire. Upon breaching the building where Kester was located, the commandos encountered Jedi Master Iri Camas, who had previously served as a commander for clone commandos in the Republic's Special Operations Brigade. Camas created a diversion that allowed Kester to flee, and then ended his own life by igniting a gas line, causing an explosion. Bry was killed by Camas before the explosion, but the rest of the squad managed to get away.
Following the death of Bry, Ennen became isolated and despondent. Squad 40 was later dispatched on a mission to locate and capture a Jedi on Coruscant, and they successfully cornered their target. Ennen killed the man, only to discover afterward that he was not a Jedi, but a common thief who had stumbled upon a lightsaber. Subsequently, within the barracks' refreshers, Ennen took his own life, using his DC-15s side arm blaster.