While i haven't played the game myself i do enjoy the various playthroughs i watched over the years of Star Wars The Old Republic Mmo and my favorites often involve the sith warrior and inquisitor play through. Often i would imagine feng being a member of the sith and like sith inquisitor/warrior you make rise through the ranks. Though i often imagine him being an unorthodox sith, while craving power and knowledge he isn't as bad as the other sith. Learning to control the emotions and amount of the darkside he uses to where it doesn't overtake him. Something very few sith are successful at doing. When creating a darth title for Feng if he was in start wars i was thinking of a rogue hero name when imagining feng in Mha that  nightstalkertbo recommended for me. I also choose a violet style lightsaber as i do think it suits the sith despite many of them using red. If one remembers it was Dark Je'daii that came to korribon and subjecated and conquered the sith species before founding the sith order. Also in kotor and swtor their were some sith that used a violet lightsaber rather than typical red

Drawn by  ahkasia
Feng Lei  alluringming