Cannonspring

Cannonspring was a fifth of the mighty Nexus Prime, and the only one of the impromptu quintet who had an inkling of his past and ultimate destiny.

Transformers: Exiles
Not long after Nexus Prime separated himself permanently, Cannonspring was tasked with defending his portion of the Blades of Time. However, his ship crashed on the planet Junkion, and he himself was knocked offline for many centuries.

Much, much later, Cannonspring was awoken by the presence of four other Transformers above him and a raging battle. These four Transformers were also components of Nexus Prime, and together they reunified for the first time in eons to help defend against the Decepticons and Star Seekers. Nexus Prime pulled forth his Omni Saber and passed the Cyber Caliber over to Optimus Prime. Although he refused to kill anyone, Nexus Prime essentially held off the Decepticons and the Star Seekers for a time, on intimidation alone. As Megatron and Thundertron left to pursue other goals, Nexus Prime reclaimed his swords and gave some last words of encouragement to Optimus Prime before splitting himself once more. Reduced to a set of five protoforms, Nexus Prime vanished into space and the annals of history once more.