Doctor Jekyll is a scientist who transformed himself into a monster that became known as Edward Hyde. Dr. Jekyll was known for being a "man about town" as a young man and did a lot of things that he regretted. He had two friends that he kept in touch with virtually his whole life. They were Dr. Hastie Lanyon and Gabriel John Utterso.
As an older man his hair grew prematurity white. He started his own experiments at home and created the Hyde serum. As Hyde, Jekyll found that he could live a scandalous life with out anyone knowing it was really him. He found this terribly amusing and set up his other identity with his own apartment and later a bank account. He even had his friend Lanyon make up his will to leave everything to Hyde if something happened to his Jekyll side.
Once Hyde kills a man Jekyll realized he had gone to far and tries to give up his Hyde self. This goes well for a while but he finds he can no longer control the transformations. He then gets a bad batch of medication that keeps him from transforming back to Jekyll. Feeling he has no other option he takes his own life.
Doctor Jekyll/Mr. Hyde is a public domain character that first appeared in a novel called The Strange Case of Dr Jekyll and Mr Hyde by Robert Louis Stevenson in 1886. With public domain status the character has been portrayed in numerous versions and ways. He is also the inspiration for characters like the Hulk.
League of Extraordinary Gentlemen
Keeping true to his origins in a lot of ways the League Of Extraordinary Gentlemen (LOEG) shows a more advanced Mr. Hyde. It is explained that he faked his death and had been staying in Paris. Over time the Hyde counterpart had grown lager and larger and the Jekyll side had become weaker and smaller. At first Hyde would only surface with ingestion of the serum. After prolonged serum use however Hyde was able to take over Jekyll when needed at shear will. The two sides have a power struggle internally. It is really the manifestation of a split personality.
Hyde first becomes acquainted by the league due to his murders of woman in Paris. Wilhelmina Murray, Allan Quatermain and Auguste Dupin track him down and capture him. Dupin even shoots off his ear in the process. Once captured they then offer him a pardon to join the LOEG. Hyde agrees.
Hyde by now is much darker and literally rips people apart and even eats them. He is the teams heavy and helps them on more than one occasion. In Hyde form, he is stated by Auguste Dupin to resemble an anthropoid ape. Despite this he eventually starts to have feelings for Wilhelmina that he just can't explain.
The Strange Case of Dr. Jekyll and Mr. Hyde
In the Strange Case of Dr. Jekyll and Mr. Hyde Jekyll's persona is that of a small man. He is dwarfish in appearance. He is bent and crouched over. As Hyde he was particularly more violent. He is first seen in the novel trampling a small girl and later he beats a man to death with a cane. Besides himself this is the only person he kills. He never seemed to have any superhuman abilities other than projecting an aura of fear in mistrust. His very look disgusted and horrified people.
The Jekyll side of of Jekyll/Hyde is a super-genius. He is highly educated with a M.D., D.C.L., L.L.D., and F.R.S. among other abilities. He is also an avid scientist who makes the serum that transforms him into Hyde
League of Extraordinary Gentlemen
Dr Jekyll has the ability to, when provoked, excited or any other emotion, turn into a large simian-like creature known as Edward Hyde. As Hyde, he possesses super human strength and durability. He also heals faster that humans, and doesn't feel much pain when injured. He sees in the infra-red and was able to spot the Hawley Griffin, The Invisible Man.