Darth Vowrawn Speculation

As per his force abilities, Darth Vowrawn appears to know some rituals, as he knew how to free the entity, however his combative applications of these rituals are questionable. As a person who is in the area of rituals, it's likely he possesses such powers as force lightning and possibly force drain. His telekinetic abilities aren't very impressive as he is easily tooled by Lord Draahg. All in all he's likely a decent force wielder, just not very combative.

As per his fighting style, I'd assume it to be Makashi, Niman, or Shii Cho. Vowrawn doesn't strike me as much of a duelist, so Shii-Cho would be likely as it is merely the basics, or Niman as it doesn't require as often training. Makashi would however be possible, as Vowrawn strikes me as having a certain elegance or sense of fashion that Makashi would compliment quite nicely. Makashi and Niman strike me as being the more likely of the three though.

Darth Vowrawn possessed a lightsaber that he kept on his person, and given his lacking skill as a combatant I find it highly unlikely that he possessed a larger arsenal of weaponry than that. I do however think it's possible that he may have had some artifacts for his rituals.

As per how he claimed his position and held it for as long as he did, I'd say he got on there through cunning, manipulation, and politics, rather than raw combative power, and held it through the same methods as well as working with allies to prevent from being toppled from his lofty perch.