Hello and thank you for the insane cat pictures.
Below you will find an example of dog heroism.
A cat in need of protection receives it and a further escalation is avoided. That is obviously good news.
But more needs to be done to get at the root of the problem that caused the initial conflict between the two cats. That dog won't always be around to bail its friend out.
Perhaps the bully cat had a rough upbringing. Maybe there was some sort of traumatic incident in its past that makes it act out violently.
And, though we certainly don't mean to denigrate the character of the bullied cat without further information, it is possible that this gif doesn't tell the whole story. Perhaps there was a provocation before the actions depicted in the gif that help explain the bully cat's behavior.
Let's not rush to judgement, and let's all hope for a peaceful co-existence between these three pets who, like us all, surely have good qualities and bad.