Hyde is created when Henry Jekyll makes a serum that separates one's good self from one's evil self, with the help of Rumplestiltskin. Hyde is used to grant Jekyll a membership at Dr. Lydgate's academy via blackmail. Jekyll also tries to use Hyde to get Lydgate's daughter Mary to reciprocate Jekyll's feelings, but Mary falls for Hyde instead and Hyde loves her too. After Jekyll finds out and ends up killing Mary, Hyde is distraught. Rumplestiltskin, feeling that the experiment was a failure due to Hyde being able to love, sends Hyde and Jekyll to the Land of Untold Stories. There, Hyde becomes the warden of an asylum, while Jekyll is the groundsman.
After interrogating and trying to kill Snow, David, Zelena and Hook, Mr. Hyde fails when they all escape with Jekyll. However, Hyde is approached by Rumplestiltskin, and they make a deal, so that Hyde can leave the Land of Untold Stories and become self-proclaimed leader of Storybrooke, bringing numerous others with him.
Hyde's reign over Storybrooke is short-lived, as he is defeated and imprisoned in the asylum under the hospital. Regina tries to bribe information from him, but Hyde is already in league with the Evil Queen, who later frees him from his cell and allowing him to escape the asylum. After Rumplestiltskin tries to kill Hyde with his dagger, Hyde obtains it and has Rumplestiltskin under his control, forcing to him to watch as Jekyll attempts to hurt Rumplestiltskin's wife Belle. However, when Jekyll ends up getting killed, Hyde also dies in the same fashion, revealing the only way to kill one's doppelganger; Regina realizes she must die in order to stop the Evil Queen.
- Henry Jekyll (good self)
- He is based on Mr. Edward Hyde from The Strange Case of Dr. Jekyll and Mr. Hyde.
- Hyde possesses inhuman strength, as well as an immunity to most magic, as displayed when a fireball from Zelena leaves him unharmed. However, he was able to be telekinetically choked by Rumplestiltskin.
- S5, E22: "Only You"
- S5, E23: "An Untold Story"
- S6, E01: "The Savior"
- S6, E03: "The Other Shoe"
- S6, E04: "Strange Case"