John

He is one of the original heroes from Team Gacha but in Mike Vs BrianGH: Part 1, Charli kills him.

Season 1

John: The Movie In John: The Movie or John: The origin, we see a young John heading to school. When he gets to school, we see DanTDM, Charli and Ms Elizabeth. When they are about to learn something, John Wick comes from nowhere and kills DanTDM. When John Wick is about to kill John, Ms Elizabeth tells John Wick to kill her instead. Then John Wick shots her. John then throws a chair at John Wick which throws him out of the room. John asks Charli if she is ok and they kiss. They run away and the credits roll. Bad Boy Vs. BrianGH (John: The Movie End Credits)

In this, we only see him when Future BrianGH tells the heroes to attack. They go and fight Bad Boy and then he runs away.

Bad Boy Vs. BrianGH 2 So we see John when Brian smiles and John slices Bad Boy so he falls to the ground. While he does that, Brian does a backflip and when John says something to Bad Boy and John Wick, John Wick says never. Then John Wick dies and John asks Brian why he did that. Brian tells Bad Boy to 'Run off' and tells John so he wouldn't kill him.

Charli (Post credits)

Although not seen, we heard Charli talking to Mike about how she wanted to kill John. Mike Vs. BrianGH: Part 1 So when we see John, he sound depressed. Then a gold trophy falls to the ground. He asks who's there and Charli appears. Then Niru throws something at him and John falls to the ground. Charli rans at John and before John can stop her, she stabs him in the head. She and Niru run off, leaving John dead. In the end credits, we see Brian and Axle walk in and they start to cry and then the episode ends.

Mike Vs. BrianGH: Part 2

We never see him in this episode or after but we do see a picture of him when Brian says that he is dead.

Season 2

Although John is dead, we think in teaser 1, we see Camper. This could mean Camper, John and even Brian could return.

Trivia
 * 1) John might've went to the same school as Brian. This might not be confirmed yet but we know Brian was going to school in BrianGH: The origin until Mike kidnapped him.