Hyde, Edward (League of Extraordinary Gentlemen (Film))
Edward Hyde was the dark side of Dr. Henry Jekyll, he was given form when Jekyll attempted to expel all evil from himself by means of a chemical formula. Jekyll was compelled to drink the formula again and again to become Hyde, and ultimately Hyde's crimes forced him/them to flee to Paris.
Gradually, Hyde mutated from simply an evil version of Jekyll to a hulking brute. Hyde (and Jekyll) was forcibly drafted into the League of Extraordinary Gentlemen thanks to Allan Quatermain and Tom Sawyer. Hyde eventually became comfortable fighting alongside the League.