Dr. Henry Jekyll
A scientist with an upstanding reputation in the community, who nonetheless is beset by evil urges which he cannot act out. Has the brilliant idea to solve his problem by splitting his good and evil sides into entirely separate people. That way, his good side would never have to worry about temptation, and his evil side would never have to worry about guilt. He makes a potion to effect the transformation, but it only works part way, giving him a second identity that was pure evil, but no identity of pure good to balance it.
- Dead Man Writing: In his last letter to Utterson, Jekyll writes that he will soon transform permanently into Hyde, which he considers his real death.
- Fatal Flaw: He disassociates himself from Hyde's evil deeds, despite the fact that he became Hyde with the explicit intent to do evil without staining his normal identity's reputation (or feeling guilt for his misdeeds).
- Good Angel, Bad Angel: Hyde is his bad angel. The problem is that the potion is incomplete, so there's no "good angel" to balance it out- just Jekyll, who's susceptible to the temptation of a life of evil without regret.
- Gentleman and a Scholar: Dr Henry Jekyll tried to invoke this trope so hard it lead to his downfall, because he managed to get three doctorates, one in medicine and two in law, and he was part of the Fellowship of the Royal Society (FRS), an award granted to individuals that the Royal Society of London judges to have made a substantial contribution to the improvement of natural knowledge, including mathematics, engineering science and medical science note . His two best friends, Doctor Lanyon and lawyer Utterson, were inseparable when they were young students. That means that Jekyll studied at least two doctorates at the same time. He has been so commited to his studies that he literally cannot enjoy his vices. That is the reason he develops the potion that converts him in Mr. Hyde. However, notice that Jekyll cannot confess what his vices were, but he confess Hyde's acts of crueltry without doubt. Jekyll never really mastered the gentleman part of this trope.
- Jekyll & Hyde: Named the Trope when he came up with a potion that was supposed to split a man's good side and their evil side.
- Hypocrite: Jekyll refuses to take responsibility for Hyde's actions, and yet the reason he takes the potion was to enjoy committing evil acts as Hyde. He even says that the reason why his evil side took over when he drank the potion was because he had created it and was drinking it for an evil reason (he muses that had he done it with good intent, he would have turned into someone completely good). The author (in a letter to a friend) called this Jekyll's Fatal Flaw.
- Mad Scientist: One of the codifiers of this archetype in classic literature despite not being mad in the psychiatric sense. He does toy with the lines of human nature and the results of his research and his experimenting are less than positive.
- Morally Ambiguous Doctorate: Dr. Jekyll was, fittingly, a doctor in two subjects: Medicine and Law. Chapter two reveals he was a M.D. (Doctor of Medicine), a D.C.L. (Doctor of civil law) and a L.L.D, Legum doctor, Doctor of Laws. And before the obligatory Evil Lawyer Joke, those doctorates were truly morally ambiguous: The Medicine Doctorate allowed Dr. Jekyll to prepare the potion that unleashed the completely evil Mr. Hyde, but also let Jekyll do a lot of good in the world helping his patients after his My God, What Have I Done? moment. The Doctorate of Law allowed Jekyll to avoid the Undead Tax Exemption for Mr. Hyde, and even helped Hyde to escape the law when Jekyll experimented an involuntary Split-Personality Takeover, but it also allowed Dr. Jekyll to make haste, where it was posible, to undo the evil Hyde has done.
- My God, What Have I Done?: Realizes that he's gone too far when Hyde kills Danvers Carew, and resolves never to take the potion again. Unfortunately, by that point he's used the potion so much that his Hyde form eventually becomes his default, and he needs the potion (which he can't make more of) to return to being Jekyll.
- Professor Guinea Pig: He is the first person to drink the potion he makes. And only, if you don't count Hyde.
- Split-Personality Takeover: After taking the potion too much, he starts spontaneously transforming into Hyde without having to drink the potion.
- Tragic Hero: He was a nice and decent man but his repressed anger and inability to accept any flaws in him (most of his friends brings up some misbehavior but nothing outside youth's mistakes) pushed him to make a potion so he can live his evil as a different person.
Mr. Edward Hyde
Hyde is Jekyll's repressed evil side, free of any desire to do good or remorse for his evil. Jekyll found being him enjoyable, as he can gain pleasure from indulgence in evil without any lingering goodness to make him feel bad about it. Unfortunately, the more Jekyll turns into him, the harder it is to stop.
- Anthropomorphic Personification: Of Dr. Jekyll's inner evil.
- Ax-Crazy: Beats Danvers Carew to death for a small slight.
- Big Bad: Jekyll's evil given form.
- Evil Feels Good: The reason Jekyll wants to be him- since he is pure evil and void of remorse, he can indulge in pleasurable vices without any conscience to hold him back.
- Driven to Suicide: Takes cyanide rather than be exposed to Utterson.
- For the Evulz: The reason he does anything, and arguably the reason for his existence.
- Made of Evil: He is the personification of everything bad in a human being (mostly untamed aggressiveness) and people reacts toward him with complete disgust and hatred due to how pure his evil is.
- Secret Identity Identity: Originally, Jekyll drank his potion to become Hyde whenever he wanted to experience Evil Feels Good. And then, it went the other way around — with Hyde becoming the "default" and needing to drink the potion to turn into Jekyll so he could hide from the consequences of his actions.
- They Look Just Like Everyone Else!: While there's something unsettling about him, he's pretty normal in terms of appearance aside being rather short.
- Uncanny Valley: Everyone notice something off about him, despite nothing being visibly wrong. It's implied that this is because he, unlike any other human, is pure evil without any trace of good.
- Would Hurt a Child: He has no problem trampling an innocent little girl just for pure fun.
Dr. Hastie Lanyon
he great Dr. Lanyon, who lives in Cavendish Square, that citadel of medicine, was one of the oldest friends of Dr. Jekyll, but for the last ten years he has seen little of him, due to Jekylls unscientific balderlash.
- Dead Man Writing: When he reveals that Jekyll and Hyde were one and the same.
- Go Mad from the Revelation: When he finds out that Hyde is Jekyll.
- Stupid Scientist: Dr. Lanyon avoids Jekyll, due to Jekylls unscientific balderlash. Jekyll is very disappointed by Lanyon, because Lanyon calls his theories scientific heresies and considers Lanyon an excellent fellow, but a hide-bound pedant for all that; an ignorant, blatant pedant. Consider that Dr. Jekyll has three doctorates, he is a FRS (Fellow of the Real Society) note and a famous doctor, in other words, Dr. Jekyll is a respected colleague and not just an eccentric, insane or paranoid person who also happens to be right.
Gabriel John Utterson
A friend of Dr. Jekyll, who becomes curious as to why his respectable friend is associating with a nasty piece of work like Edward Hyde.
- Amateur Sleuth: His function in the original story, trying to figure out why Dr. Jekyll was covering for Hyde despite them having no known relationship.
- Demoted to Extra: In most adaptations, since the twist is better known than the original premise of the story.
- Perpetual Frowner: Mr. Utterson the lawyer was a man of a rugged countenance that was never lighted by a smile; cold, scanty and embarrassed in discourse; backward in sentiment; lean, long, dusty, dreary and yet somehow lovable.
- Pinball Protagonist: He doesn't interfere much in the story's conflict, with the exception of serving as the impetus for Hyde to commit suicide at the end. He's basically there so that the 'Jekyll and Hyde are one and the same' twist would remain a twist.
A well-loved member of Parliament who has the misfortune to cross Mr. Hyde.
- 100% Adoration Rating: By all accounts, he was well liked. Hyde only killed him because, as the personification of Jekyll's evil, he was incapable of positive feelings towards another.
- Kick the Dog: Hyde beats him to death because of a minor slight.
- Posthumous Character: By the time he's introduced, Hyde is already wanted for his murder.
- Small Role, Big Impact: His death was such a horrific, pointless act of evil that it enraged the entire nation against Hyde and caused Jekyll to have a Heel Realization about Hyde's antics.