Harry (The Supercat Video Universe)

 The Supercat Video Universe: Volume 1 

Harry was shown to be Callum's friend in the Video Universe as he was always with him.

During the Supercat Video Universe him and Callum put on disguises to go looking for Meme Man. Upon finding Meme Man's clothing laying on the ground, he is shot dead by Bill but is brought back to life via the 'Time Reset' that occurs when Jamie's magic is sent back to the Time Veteran.

 The Supercat Video Universe: Volume 2 

In Callum's dialogue at the very beginning of volume 2 Harry is mentioned to have gone travelling the world and as a result misses the events of volume 2. His actor hasn't appeared on the channel since volume 1 so it's likely we won't see the character again.