Cassiopeia, Serpent of Demacia
Since Demacians seem to be the theme of late, I present Demacian Cassiopeia. I based it heavily off the incredibly well done Demacian Irelia skin by Thandrophir, though I did try not to wholesale copy it. This skin replaces the Siren Cassiopeia skin, if you want to use it on her normal skin use a tutorial.
There is a slight issue with the inside of her mouth being blue, as far as I can tell this is an issue with the model using weird parts of the texture for her teeth, etc.