This is my personal interpretation of Toa Nidhiki. Click it for a bigger view.
Breaking from the way I normally work, I searched the Web for examples before starting on this guy because I knew wih the popularity of Toa MOCs, there were sure to be some previous attempts. Sure enough, there are some out there, but I didn't look them up for inspiration -- I looked to see what was already done to make sure mine wouldn't look like any of them!
I used this Nidhiki picture as my main inspiration during the build to get the appropriate mix of colors. Since he was a Toa of Air, I wanted to give him wings, and the Mistika pieces looked just right. It was extremely tricky and took hours to get them mounted, because I wanted them to fold into a diamond neatly behind his body. I ended up setting them up on a beam that would slide straight down about 3/4ths of an inch to extend the wings, and move back up to keep the front profile heroic in nature. When the wings had a fixed mount low enough to fit under the arms properly, they looked all wrong when folded up.
Finally, there's the whole deal with the Air Scythe. I'm sure there are plenty of concepts about how this should look, but this is my simple take on it, using a piece from the TRU titan Toa Mata Nui set, mounted at an angle and with a curvy handle. In putting this together I just looked at pictures of real scythes and tried to find what would approximate that look without inspiring images of the Grim Reaper.