Once just another Toa, this guy was manipulated and mutated by the bad guys.
Pictures are taken against the light source because I think it would be too much of a spoiler.
He has a larger backstory and an actual name; Rohgak is the bad guy. As you can see, the legs are yet to be built. He's got a dark/trans blue and yellow/keetorange color scheme, with a lot of black. The trans green accents are supposed to be sea weed.
Edit: Here are pictures with better lighting.