It was him, it says so in the SWTOR Encyclopedia - his Voice was created soon after that event because he feared another attack could happen again and wished to protect himself (Basically he did it out of fear, implying he nearly died.) It's also canon that the Emperor has no emotions, and has been that way since birth. But that's kinda irrelevant. But yeah, the 'Lord Emperor' would be struck down by lightsabers like a pinata and then gobbled up by Nihilus like he gobbled up Nathema. Oh and in between those events Traya will Force lecture him.
P.S. I like your sig, I actually sang it.
I'm not exactly sure if wookie is correct - but then from description of the fight we can clearly say that fighting them was rather easy, I wouldnt be surprised if he toyed with them. You dont need emotions to have a sense of humor. Nihilus would dissolve just by standing near the Emperor. He is definately much wiser than old baba.
so firstly you compliment me and now you start to flirt - I'm hum it all the time