Emperor is a large Utahraptor, he thinks the world of himself and believes everyone and everything should bow to him. He has seen leaders of other species wear jewels and other shiny things, so he likes to hoard anything that will make him look alike. No matter what he wears though, he does try to make sure it is lightweight and not in the way as he does a lot of running around.
He found an interest in collecting gems and shiny valuables so he collects any he finds. If you steal food from him, he could care less. If you steal one of his "shinies", you'll be in some big trouble with him. He seems to think that if he desires it, it's already his.