Dr. Jekyll & Mr. Hyde charater design

Character and Environment design I made for the Novel Dr. Jekyll and Mr. Hyde.

"Dr. Henry Jekyll feels he is battling between the good and evil within himself, thus leading to the struggle with his alter ego, Edward Hyde. He spends his life trying to repress evil urges that are not fitting for a man of his stature. He develops a serum in an attempt to mask this hidden evil. However, in doing so, Jekyll transforms into Hyde, a hideous creature without compassion or remorse."
In my version, Dr. Jekyll, which suffers from asthma discovers the amazing respiratory system of frogs, and when he develops a serum as a result of ADN manipulations, he breathes it and becomes Hyde a cruel creature with amphibia characteristics. 
He has to live and hide in his secret lab when he transforms into Hyde.
You can see part of the process and some sketches I made for my concept art class.