Gentlemen, behold: Helryx "Described as looking frail and battle-scarred, she's possibly one of the most powerful Toa in the universe, with unparalleled control over her element honed over many thousands of years."
I was going for a bio-mechanical appearance, but tried to avoid the movie style, with its exposed(!) muscles and the weird fleshy-looking masks that some characters had. She also ended up looking somewhat like a Toa Mata, with asymmetrical arms, two-fingered hands, and a similar torso structure.