Here’s my entry for that canon contest with Helryx. More pics can be found there
As for her appearance, she went though thousands of battle and survived every one of them. I imagine she has to be combat ready and a skilled fighter to do all that. To me, her frailty comes from the intense and numerous battles she fought in her life. Helryx is the oldest toa, so I figured I would try to bridge the gap between system and technic pieces, a combination That Takanuva would not have been able to recognize.