It does't require much investigation.
As Master Xi moves toward the tree line, the flames that are ravaging the jungle trees is suddenly put out, as if with a powerful wind. From the smoke emerges a figure, proudly marching out into the open.
Rather as you expected, the figure is robed entirely in black.
Brath stands proudly beside you, Rianna. He ignites his lightsaber, the blade and hilt admittedly much larger than your own despite being modeled off of it.
Nuvar is just behind you, Dak. He has his lightsaber out as well, but it is shaking in his hands. He is afraid.
"Oh, come now, and end all this?" the Sith Lord asks loudly. He reaches up and drops his cowl, revealing the jovial face of a human with messy brown hair and a slight scruff on his chin. "But I'm having so much fun! I mean, look at this battle! It's so chaotic! Your men are performing admirably, I'm sure they don't mind having something to shoot at."
The Sith Lord is portrayed by Joseph Morgan.
The Dark Side obscures this one, but you sense his amusement.
"What's confusing about this?" Lord Rallo says. "I am the only being that is REAL here. Everything exists as I have willed it to. It's not a difficult concept, Jedi. But sometimes I even surprise myself! I've subconsciously imbued you with some of your own will. Ah, I'm magnificent..."