Originally posted by tdtd
It just says that "It instantly kills its opponents". It doesn't go further than that but there is no reason to assume it can kill non force users and can't kill force users. "It instantly kills its opponents" seems universal, if it wasn't they'd have been more specific, that's my opinion.
First off, I want to know where you're pulling this information out of, and if it's Wiki, you should go chew on some broken glass.
What is with you people and instakills? So you're all saying that Kun, Traya and Luke can instakill Ragnos *rolls eyes*, why would their be no defence, most of the instakills (exception being Emerald lightning) originated from the Ancient Sith, so why would they have no defense, if they did, then wouldn't Ragnos be instakilling in between 150 years of ruling?
Actually, it's likely that Ragnos and some of his peers can easily defend against such attacks. His power was immense, and he already demonstrated knowledge of force draining. Traya would be a pipsqueak in front of him, and Kun wouldn't be much higher than that. Luke could try his green poprocks lightning attack and Ragnos will blink and send him into space.
Considering no one tried to snuff him in his sleep and take over for over a hundred years and that he died a natural death, I'd say it's not a stretch to think he can defend against most attacks period, let alone most "instakills".
Now, on the topic of the fight...
If Ulic can get in close, he'd own her beyond the telling of it. But if she can and does use her force drain (Or perhaps even just her regular force powers, which are considerable) he's going down. I don't see him blocking that attack. Ulic never demonstrated a heavy knowledge of the ancient sith.