Ezra is silent for a second, very reluctant to specify.

"They usually use titles or wear masks, or both. I know one. The Sith Master's right hand, because I know someone who was close to them, before. I'm...almost certain they haven't embraced the Darkside and the Sith, yet. They'd have to hiding it really well."

Surely Ahsoka or Obi-wan, or someone, would have had some clue? But then-

"Or maybe I'm wrong. The Master is already hiding in plain sight."