His Story Repeats Itself

When it comes to a character's Backstory, there is usually one event that stands out among all the rest and made the character what they are. They watched their parents die. They killed someone... or failed to. They let someone down. They ran away from something. This event will surely be the core of their Dark and Troubled Past, something that they have been spending the rest of their life coping with, living in the shadow of, accepting, or just trying to put out of memory...

Simply put, backstory is a theme. And themes need resolutions. Thanks to the Law of Conservation of Detail, you can probably bet that the resolution to a character's backstory will involve them facing the exact same or similar event that haunted their past, allowing them to conquer their demons once and for all... or die by them. Such event is guaranteed to be a climax of some sort.

History tends to repeat itself in the following ways:

Character finds themselves faced with the same decision as before. They'll either make the right decision this time, or fail the same way again.
Character finds themselves faced with a danger, obstacle, or enemy from their past, something they have a very strong, personal grudge against. If they failed the first time, or perhaps succeeded out of pure luck, they'll be able to stand up to it with their own skill this time... or fail again.
Character finds themselves faced with the same type of tragedy from their past. This time, they'll be emotionally mature enough to handle it.
Character sees someone else going through the same series of events they did. They'll have a chance to help... or use it against them.

Note that a simple Chekhov's Gun cannot qualify. It's also not a realization, symbolic or otherwise, that they've failed or accomplished some life's goal or made some dead person happy. This needs to be a full-blown parallelism between what happened before the story started and what happened during the story.

Compare with Book Ends and My Greatest Second Chance.

Has nothing to do with putting your Michael Jackson album on repeat all night.

Examples of His Story Repeats Itself include:

Anime and Manga

Juri in Revolutionary Girl Utena has in her backstory been in a romantic triangle with Shiori and another nameless boy from the duelling club. The boy was interested in her, Juri was in love with Shiori, and but Shiori convinced the boy to go out with her instead. During the Akio Ohtori Arc, Rukia, the former captain of the Duellist club reappear, and starts going out with Shiori, although he's really interested in Juri and is trying to make Juri forget her infatuation with Shiori.
Daphne in the Brilliant Blue ends with Maia applying for the Oceans Academy again, like in the first episode (in which she failed)... Or does it?
For some students of the Afterlife High School in Angel Beats!, one of the reason you are there is to repeat your life's story, and making the right choice this time around. That, or simply having a good enough time.
In Fullmetal Alchemist, Scar starts out a member of an oppressed ethnic group, the Ishvalans, wanting revenge on those who nearly wiped out his people, namely Amestris. By the end of the story, he pays an instrumental role in saving Amestris.

Comics

MAG-ISA—the entire comic is all about the recurring theme of being alone. Both among the protagonists and antagonists.

Film

In Hook, Hook gets eaten by the (apparently not dead) crocodile that bit his hand off.
Top Gun: The main character's co-pilot is killed in a freak accident after their plane stalls because they flew through another plane's "jet wash." In the final battle, the same thing happens, with a number of implications played out (Maverick keeps his plane in the air this time, but loses his nerve, and starts to flee before having an Underdog Comeback moment and saving the day).
In Kung Fu Panda, Master Shifu fights a rematch against Tai Lung, his old apprentice-turned-evil, but loses again.
- You could also say Tai Lung's story repeats itself too—after being denied the Dragon Scroll, he is defeated, paralyzed, and imprisoned; twenty years later he escapes, tries to claim it again, and is again defeated, even when he attempts to use on Po the same move which had defeated him the first time.
- Perhaps more importantly, the parallels between Tai Lung's and Tigress' training, and Shifu's differing reactions.
In James and the Giant Peach, James' parents were killed by a runaway rhinoceros. Sure enough, in the movie version, the rhino reappeared.

Literature

The entire Harry Potter series revolves around how Harry miraculously survived a death spell from Voldemort, and chronicles how he gets strong enough to finally face him in a rematch.
At the very beginning of Warchild, Jos is abducted by pirates and abused by their captain Falcone. He escapes. Much of the rest of the book is spent showing him coping with that experience and the difficulties he has in trusting people because of it. But you know Falcone will be showing up again. Sure enough, in the climax, he captures Jos yet again and repeats the same pattern of abuse. And this time Jos can't even repress the memory. Unusually, Jos isn't able to face his demon or die by them. He's rescued. Not that it stops him from killing Falcone the third time they meet, when it's Falcone who's been captured.

Live Action TV

The Star Trek: The Original Series episode "Obsession", where Captain Kirk couldn't save people from a monster.
Birds of Prey did it with Black Canary, recreating her traumatic kidnapping in order to allow her to come out ahead and prove to herself that she was stronger. Or something.
This is often used in Highlander the Series. In the past an Immortal enemy killed someone Duncan cared about. In the present Duncan must face him again and this time stop him from killing Duncan's friends and/or lover.

Video Games

The Metal Gear Solid series deserves its own section.
- Metal Gear Solid: Snake's inability to kill Fox to ensure an easy victory, because he had learned from his mistakes of killing Fox and Big Boss in Metal Gear 2.
- Metal Gear Solid 2: Subtle one. Otacon loses his father - and almost his sister - due to a drowning suicide by the former. If he had been there, he would have been able to save them - but he was in his room having sex with his stepmother at the time, and therefore didn't respond to his sister's cries for help. At the end of the Tanker chapter, Snake calls for Otacon to save him from drowning. This time Otacon saves him by riding a boat out onto the sea in a thunderstorm just to pull him out of the water.
- Metal Gear Solid: Portable Ops: Big Boss assassinated The Boss, but, when his old friend Python begs for him to finish him off the same way The Boss did, he tries to save him instead.
- Metal Gear Solid 4: Naomi dies in similar circumstances to Sniper Wolf (even the music is the same), and Otacon is overwhelmed. However, instead of grieving, he quotes the line Snake uttered after Wolf's death ("I don't have any tears left to shed"), and shakily gets on with life.
Devil May Cry: Dante - who lost his his mother as a child - nearly lost Trish as well, who basically is a demonic clone of her.
Shadow from Sonic Adventure 2 is shocked into realizing his past after Amy Rose coincidentally uses the same phrase that the late Maria Robotnik did, and thus decides that, to make it up to Maria for the damage he's done, he'll stop the Space Colony ARK from hitting the Earth.
- Though it probably wasn't real, Shadow the Hedgehog featured a level where Shadow could have the choice to stop the G.U.N. soldiers from killing Maria.
Archer's backstory in Fate/stay night works this way, putting him in his current position at the game's beginning. As a human, Archer when he was called Shirou was unable to save people from a disaster, which eventually led to his making a contract with the world to prevent the same thing happening in his adulthood.
In Blaze Union, Gulcasa loses a number of people important to him through death and betrayal. He blames this on his own personal weakness (although every circumstance was pretty much out of his control) and vows to gain the power that he needs to really protect his loved ones. Three years later, another large-scale conflict starts; whether or not Gulcasa is capable of protecting his allies depends entirely on whether you're playing Yggdra Union (he can't) or Yggdra Unison (he does).
Tatsuya Suou's history in Persona 2. He pretty much threw the weight of the world on his shoulders and tasked himself to destroy Nyarlathotep's plans before they started so his friends wouldn't have to suffer. He failed.

Western Animation

Avatar: The Last Airbender: Happened over and over again with Zuko. Most notably was his final showdown with his father where he was about to get burned once more, but instead deflected his father's lightning

Webcomics

A Broken Winter: After failing to save his son's life, Kuroda is given the chance to save his best friend's son, Kokkan, which he does eventually. He then raises the child in his son's place, even going so far as to alter public records to keep Kokkan's true identity (wanted son of a terrorist) a secret.