I'd say "Master" is masculine enough that it seems an odd title for someone who doesn't even have hair or facial features for purposes of making their gender difficult to tell to choose. But that could just be me.
Ruler, Monarch, or Sovereign might work, though. Edit: As might Warden.
"Out there" is good. "Soul of the Ice" is pretty close to the concept, actually, except they weren't quite born from it...
Would the description of the person be of use?