Dead Inside

Sabre's been in the Steves' world for quite some time. He chose to stay there, with all his friends, and live there for the rest of his life.
But he's staying there for far too long. His power to teleport to different dimensions and realms has become overwhelming and it is slowly taking over his body and killing him from every bone to every organ in his body.
Sabre is now wanting to hide this new secret from his friends, he can't worry them. But what will he do when his friends do find out about his secret? What if his power takes over too much of his body, and it will be too late to save him?