Without him all are lost....in space...cause he's the astromech droid
R5-D4 was built by Granpappy Victus on Uvena Prime during the time of the Old Republic. At the time Victus considered R5 his fifth child and gave him the name Fae Victus, Shistavanen for Fifth Bloodmoon. R5 grew up with Victus’ children and was always considered part of the family.
One day Victus’ eldest son William Raynard Victus Jr. wished to leave Ulvena Prime and become a starship pilot. Not wanting him to leave alone Granpappy Victus entrusted R5 and a beat up old Ghtroc freighter to his son and gave him his blessing, wishing them both well in their travels. However, Victus Jr. fell on hard times and eventually lost R5 in a Sabacc game.
Sometime before being assigned to Fin Nunb’s ship he was actually the “copilot” of an X-Wing on Dantooine.