Originally posted by UrsumelesHe's a low level entity.
WHAT? LOL. 😆
"Valkorion is an ancient Sith entity with the power to possess and control the bodies of others, using them as puppets to enforce his will on the galaxy. The Immortal Emperor is his latest mask and Zakuul his greatest, most ambitious endeavor: an idealistic playground where he can shed his past and experience a new life unburdened by archaic Sith teachings. A manipulative survivor, Valkorion pinpoints the weaknesses of both friends and enemies alike, twisting them to serve his purpose. He believes the entire galaxy is his to shape and will stop at nothing to reach his goals."
From (Star Wars: The Old Republic: Knights of the Fallen Empire: Codex Entry titled "Valkorion."
Valkorion and Plagueis aren't touching Luke, they're practically fodder to him. Only the combined effort of multiple DE Sidiouses can penetrate his Force barriers, and that's only when they amp each other and weaken Luke with their nexus and Battle Meditation powers. Or they could distract Luke with their mental powers while the rest kill him conventionally. I'd say two would be enough to take him down, but it would take everything out of them. Three would beat him solidly. Four would stomp.