Fives: ARC-trooper, the second last survivor of Domino Squad. Because of him we have Good Grandpa Clones in Rebels.

Echo: ARC-trooper, the last survivor of Domino Squad. After he went boom, he was taken by the Techno Union and turned into a walking-talking USB stick. He spent all his time in captivity reading the enemy’s reg manuals.
Канон.