Kevin Leab Thong, also known as Tarrer’s Costume and Props, has made some complex costumes. He seems to focus on characters with armor and has made replicas of two sets of armor from The Witcher 3. Regardless of the material he starts with, he does an especially impressive job with making it look like metal. For his Imlerith ensemble — Imlerith is a warrior of the Wild Hunt and a villain in The Witcher 3: Wild Hunt — Kevin crafted each piece of armor by hand, painted it, and aged and weathered it. The latter part involved scratching and scuffing up the armor and giving it multiple layers of paint. Before that, he had to cut and fit several pieces of foam together. It looks like he spent a couple of months on the project.
Be sure to look at the in progress pics below and on Facebook. Seeing the humble and often simple beginnings of elaborate costumes like this one helps me feel like I can make anything I set my mind to.