Well Darth Malgus doesn't want anymore to do with an enemy who can deflect his attacks, fight him on equal terms with a lightsaber, and suck the life out of him from a distance. Trooper, "Is it dead?" Malgus, "No. And we will not be here when it wakes." Careful what you go looking for, because it just might find YOU instead.
If this were strictly a lightsaber fight then Malgus could win... But Nihilus eats entire planets with the force. He is a literal wound in the force so large that he consumes the life essence of almost everything around him. One of the only ways to destroy him was to be an equally large wound in the force that couldn't be consumed in the same way. Hence the Exile.
First these Sith trooper uniforms are straight fire. Second… so were those lightsaber strikes. This was dope af. Never a disappointing video from this channel.