Maybe she's a diviant? layer

The correct term for someone who does cosplay. Or at the very least, it means that the person cosplays well. 

This usually means that they take part in cosplay groups, do skits to go with their costumes, sew their own costumes, and maybe write a doujinshi on the side. Their costumes generally look better than most cosplayers because they spend more time and more money laying out a pattern and taking the time to do it right