The Koloss creatures are blue skinned vicious monsters from the Mistborn series. Koloss are humanoid, and their connection to humans is explained in the last book of the trilogy. They have blue skin and when they are little, about six foot tall, their skin hangs loosely on them. When they are fully grown, around 12 feet tall, their skin is stretched so thin it starts ripping and bleeding. They are bred and exist strictly for war, they can survive on basically nothing, and are easily controlled by the Lord Ruler.
This is a quick pencil sketch I made a week ago.
Here is the more detailed drawing I made around the same time which I finally got around to touching up both with the pencil and in Photoshop. I’m really thinking about doing a digital painting of one of these guys because they’re described very vividly in the books.