Think I'm about ready to accept it. Had me concerned for a moment until you said he isolated himself, lol. Historically, Revan was a great pilot... so it's kind of hilarious that Markus is horrible. We have a pretty diverse cast in terms of personality, I'd say! 

Small note: Looking up and reading a lot about the Sith could definitely be a secret, but I feel like his greatest secret would be killing in rage. Killing quite a few, in truth.

Ah, there it is. Did a quick scan before I found what would be something to edit. Being an exiled jedi knight, he wouldn't have access to the masters anymore. He'd have few holocrons or masters to learn these forms from in that kind of abundance. I'd suggest you cut down the number of forms he knows, and the number he has mastered.