It was actually the real Emperor, that we can say for sure. And he was struggling in that battle, he almost died. And he never used his lightsaber, just Revan's. And the Sith Emperor doesn't have a sense of humour.
And he ain't going to be drinking Nihilus. He's a black hole AKA nothingness. You get sucked in, you not consume it. Nothing to drink I'm afraid.
EDIT: Lol are you always high?
we cannot say if it was him and most probably it wasnt him. I didnt say that it was his lightsaber - of course that he does, hes such a lovely person after all.
to bend a black a hole with a force and consume it like a juice is Lord Emperor's way
I'm always right and never high - or maybe, you mean my social status, but then, thank you.