Evil twin

Early Mermay painting, drawn from mind. I was trying to draw to characters from imagination, they supposed to be twins, but one of them is stereotypically good, and other evil. Evil mermaid took diary of her sister and wants to read all of her secrets x) Challenge was to design them that way so everyone who will look at the drawing would understand who is who, I inspired by designs of animation artists and wanted to draw this task myself.