It's one of many character equipment sets I made for our fish-controlled medieval-robots game called Feudal Alloy.

Here's a short timelapse video of the design process: https://www.youtube.com/watch?v=TFNKXJF6taM

Some info about the game can be found here:
http://FeudalAlloy.com
or here:
https://store.steampowered.com/app/699670