Recap / X-Men S5E9 "Descent"

The year is 1888, way before the formation of the X-Men, and a criminal is running rampant in London. Meanwhile, professor James Xavier reveals the story of his friendship with fellow scientist Nathaniel Essex to the cops as they all try to capture his former friend and find out the machinations behind the criminal's spree.

Tropes:

• Adaptational Backstory Change: The episode maintains Essex being a Victorian scientist and contemporary of Charles Darwin, but Apocalypse has nothing to do with his transformation into Mr. Sinister. Essex using himself as a test subject instead causes the change.
• Adapted Out: Apocalypse, Scott and Jean don't appear in this episode.
• Berserk Button: Due to the customs of the time, Essex is not allowed to treat his own wife. James talking about how it will take time to treat her prompts an angry reaction from Essex.
• Big "WHAT?!": Lord Grey's reaction to Essex giving Rebecca secret treatments.
• Big "YES!": Essex when he finally makes a breakthrough on his work.
• Broken Pedestal: Essex very much admired Charles Darwin and was devastated to see him shun his work. When he finally achieves a breakthrough, Essex proclaims that he has outdone his former idol.
• Call-Forward: "Sinister" gets mentioned more than once for this effect.
  James: They speak of sinister experiments you are rumored to perform.
  Essex: Sinister? I'll have to remember that when Queen Victoria knights me.
• Connected All Along: The future Mr. Sinister turns out to be the Evil Former Friend of Xavier's ancestor and the husband of Jean's. It's implied that the experimental treatments he gave to Rebecca are why Jean would develop her mutant powers.
• Delayed "Oh, Crap!": The full extent of her husband's transformation prompts this.
  Rebecca: What have you done to yourself?! [realizing] The treatments! What have you done to me?!
• Didn't See That Coming: Cornered by an angry mob, Essex suddenly fires energy blasts from his hands. He then looks at his hands in complete surprise.
• Disastrous Demonstration: Essex's demonstration of his New Men's abilities to Darwin is one of these, though the disaster is more one of expectations than physical — after promising something revolutionary, he produces a man who produces a slight electric charge, and a man who can boil water with his hands. Darwin is quite reasonably unimpressed.
• Downer Ending: After years of trying, James fails to catch his Evil Former Friend and doubts he ever will.
• Everyone Has Standards: Seeing the conditions of the asylum, James proclaims that not even animals deserve such horrible treatment.
• Evil Former Friend: James Xavier and Essex were colleagues that were good friends, albeit at odds over Essex's views about science. Seeing what Essex had been doing to those in his asylum cause James to denounce him as a monster.
• Evil Laugh: Essex gets a few of these examples, such as when he achieves his breakthrough and when he escapes James in the end.
• From Nobody to Nightmare: Essex starts out as a friendly doctor deeply worried about his wife's declining health and wanting to find a way to spare the rest of humanity such issues. His research being denounced as blasphemy and insane (including by his idol Charles Darwin, no less) led to him becoming obsessive in his work and transforming into Mr. Sinister.
• A God Am I: After his breakthrough, Essex proclaims himself a creator.
• Happily Married: Essex truly loved his wife, Rebecca Grey, and was initially motivated in his work to find a cure for her condition. The marriage collapsed when she saw what he had become and feared what his treatments had turned her into.
• Healing Factor: After his skin changes, Essex accidentally burns a finger and is amazed to see the injury completely heal itself. Later, one of the mob manages to strike him with a shovel, but this wound is also healed instantly.
• Historical In-Joke: In Whitechapel, the local inspector alludes to inhuman atrocities and Mr. Sinister later scolds Jack for failing an assignment. It's strongly implied that this is none other than Jack the Ripper himself and that he was simply a means for Mr. Sinister to acquire genetic samples.
• Hope Spot: James believes he has finally cornered Essex in a flat, only to find the room is already empty. The newly christened Mr. Sinister is already on a boat leaving Europe.
• I Did What I Had to Do: Essex justifies the depravities in his asylum by saying the inmates would receive far worse treatment elsewhere. He genuinely believes he is helping them.
• Irony: After Thomas Flannery is outright denounced as a demon from Hell, James finds him in a church begging God for His mercy.
• Jack the Ripoff: Subverted. The episode opens with a red-eyed man with facial hair stalking a woman in the streets of Whitechapel. You're made to think this is Essex himself, but the ending reveals it's instead one of his creations. Essex is even irritated that Jack killed a possible subject instead of bringing them in alive.
• Jumping Off the Slippery Slope: Essex began his research in the hopes of helping his wife. His research being shunned by Charles Darwin and other scientists caused him to go to more extreme lengths and become increasingly obsessive.
• Little "No": Essex when his "children" escape the asylum. He does it again when cornered by the mob before realizing he can actually defend himself.
• Mythology Gag: "New Men" is how James describes Essex's creations. That is also the term used by another Marvel Evilutionary Biologist, the High Evolutionary.
• Not Helping Your Case: Essex's underwhelming demonstration of a pair of New Men's initially meager abilities fails to impress Darwin, who is understandably quite offended at being promised revolutionary wonders and shown what appears to be carnival tricks. Essex's response is to not only rant about Darwin's failure to see what he's achieved, but declare that his discoveries will allow mankind to become godlike in power. Darwin naturally goes from seeing Essex as most likely a self-deluding fool (and at worst a fraud), to seeing him as megalomaniac.
• Obnoxious In-Laws: Lord Grey eventually towards Essex. They initially got along rather well, even as Essex's reputation starts to be considered blasphemous, due to how much Rebecca loved him. Rumors of Essex's more extreme practices cause a falling out and the final straw is learning that Essex gave Rebecca secret treatments.
• Oh, Crap!: The man who struck Essex with a shovel has this reaction to the Healing Factor.
• Origins Episode: For Mr. Sinister, showing his life before his transformation and his downfall.
• Power Incontinence: Essex's patients at the asylum were still being experimented on when James managed to help them escape, so they can't properly control their powers. Thomas Flannery in particular accidentally blasts some buildings with fire.
• Pragmatic Villainy: Essex ordered Jack to bring in a particular subject alive, as a living person was what his latest experiment required.
• Red Eyes, Take Warning: Essex displays this after Rebecca knocks off his glasses.
• Spared by the Adaptation: Rebecca doesn’t die.
• That Man Is Dead: "Essex is no more. From this day forward, you shall address me as Mr. Sinister!"
• They Called Me Mad!: In the face of his work being denounced, Essex vows to prove he's right. After achieving a breakthrough, he mocks his former idol Charles Darwin for having called him mad.
• What Have I Become?: After seeing what her husband's turned into, Rebecca starts to wonder what his treatments turned her into.
• Whole Episode Flashback: An older James tells a local inspector the story of Essex's downfall.
• Wrong Genre Savvy: Flannery is a fire-throwing mutant suffering from Power Incontinence, but to Victorian locals, he's a demon unleashed by the Devil.
• You Fool!: Essex gets a few of these moments, such as when the mob corners him or when Jack fails to bring in a subject alive.
• You Monster!:
  • The inspector that James talks to openly doubts that any man could be responsible for the sheer atrocities committed in Whitechapel, feeling that only someone truly inhuman could be doing all this.
  • The mob denounces Flannery and the other inmates as this. James urges them to show mercy, saying these poor souls had no choice in what they are and were actually victimized by the true monster.
    James: The true monsters walk amongst us undetected. There is your monster! Nathanial Essex!
• You're Insane!: Charles Darwin denounces Essex as mad for talking about how his research will allow men to become tantamount to gods. Later, after seeing the conditions of the asylum, James denounces Essex this way. Essex is naturally displeased by these accusations.