"Knuckles"

"Knuckles" was a split persona who was made in the Supercat Video Universe by Jamie who gets him to track down Sonic Callum.

In the finale to the Supercat Video Universe he tracks down who he thinks is Sonic Callum (but it's actually the original Callum wearing his Sonic hat) and they fight. Knuckles loses to Callum and Callum forces him to tell him where Bill and Jamie are.

Knuckles ditches Callum once they find Jamie and Bill but he comes back later in the finale to help Callum.

Due to the 'Time Reset' erasing any events after "The Origin Story" Knuckles never actually existed.

After the Time Reset, Knuckles appears as a figment of Bill's imagination but then disappears when Bill dies.