Belated Happy Ending

A story has an open ending. Did Bob win? Did Alice survive? Did the world find out what really happened? Either we just don't know, or Word of God says it's all open to interpretation.

Years pass. Then the author decides to return to the story, and a sequel or semi-sequel is released. It turns out Bob did win, Alice did make it out alive, the world found out about the truth, and everyone got their happy ending. This isn't just Word of God - the sequel itself shows us what happened after the end of the first story.

Compare I Knew It!, which is about fan theories being proved right, whereas a Belated Happy Ending is specifically about the characters (regardless of fan theories). See also Maybe Ever After, an ending which this trope can resolve.

Since this is an ending trope, needless to say there will be spoilers ahead.

Anime/Manga

 * The ending of Digimon Tamers was fairly ambiguous, but then the sixth movie came out, showing that everyone did, indeed, reunite with their Digimon.
 * And then it might have fallen under Canon Dis Continuity.

Comic Books

 * In Elf Quest, the original authors eventually got back to writing the comics, and saved several characters who were Left Hanging in old plotlines: Ahdri gets rescued from the caves in which she was trapped for centuries, Strongbow and Moonshade are granted another daughter, and The Broken One finally gets healed.

Fanfiction

 * Back in 2006 Asatsuki Dou released a horribly depressing Touhou doujin called "Happiness". Not quite two years later they released "Happy End", which exists entirely to give "Happiness" a happy ending.

Film

 * At the end of Advent Children (one of the sequels to Final Fantasy VII),  are finally shown to be reunited in the afterlife.
 * And it isn't until the end of the film that Cloud shed the emotional hangups that kept him for being with Tifa nad embracing a more proactive role in healing the world.

Literature

 * A sequel to The Darksword Trilogy was written a few years after the series was completed, in which  turns out to be alive, the war is finally settled, and Joram gets to finish all of his unfinished business.
 * In William Goldman's Brothers, (a character who was thought to have died in Marathon Man) is brought back, and finally gets a chance to reunite with Marathon Man's main character, Babe.
 * In William Goldman's Buttercup's Baby, the short story sequel to The Princess Bride, we find out that the characters did escape from being chased by Humperdinck in the original novel's open ending. Buttercup and Westley have a baby (as the title says). Interestingly, the story also wraps up some plot elements from Goldman's unrelated novel Control, although it's a bit of a Gainax Ending.
 * The Club Dumas by Arturo Perez-Reverte has a group of bibliophiles competing over the collection of rare manuscripts. One of them is a treatise on sword fighting. Its author is Don Astarloa, the main character from his previous book The Fencing Master, who'd spent most of the story trying to write a treatise on fencing. Apparently he finally finished it.
 * The ending of Lois Lowry's The Giver is extremely ambiguous and heavily implies that . In the two other novels set later in the same universe, we learn that.
 * A child strongly implied to be appears briefly in the same sequels.
 * Blindness: One person regained her sight in the end of the novel, but the sequel takes place years after forgetting the whole incident.

Live Action TV

 * In the Christmas Special of The Office UK (which was filmed after the main series was completed), Tim and Dawn finally get together.
 * Anthony in The Royle Family spends his teen years being ignored, lightly bullied by his father and unemployed. When he does married and get a good job, his wife cheats on him and leaves him. Then he meets Saskia, a beautiful nurse, falls in love and has another kid.
 * After the Maybe Ever After that closes Spaced, the "Skip to the End" documentary demonstrates that Tim and Daisy eventually had a little girl together and are still living in the same flat.

Video Games

 * In the best ending of Final Fantasy X 2, Tidus and Yuna from Final Fantasy X finally end up together.
 * In Final Fantasy V, Gilgamesh was lost to the Void. Three games later, in Final Fantasy VIII, he returned - and has appeared in pretty much every Final Fantasy since. Even, retroactively, the ones before V.
 * However, Gilgamesh's appearances before Final Fantasy V in The Remake by Squire Enix act more like Bonus Boss to keep the fans reminding of him. In other word, he appear in them for no reason related to plot, simillar to the archfiends from the first game, Doomtrain, and Ultros in Final Fantasy IV the After Years and Dawn Of Soul.
 * Then Dissidia 012 Duodecim came out, and revealed, once and for all, that Gilgamesh is alive. Wandering dimensions at the mercy of the Rift, but alive, and determined to get back home.
 * Barring the possibility that his sacrifice against Necrophobe occurs AFTER his travels. The Rift is a weird place like that.
 * He tells Bartz that he wants a rematch just before self-destructing against Necrophobe and references that in Duodecim, meaning he took part in the battle before Duodecim. Or the Rift is really that wierd a place.
 * The ending of Final Fantasy VII was vague as to the outcome of the cast and human beings in general. A post-credits scene which showed exactly ONE of the party members still alive 500 years later (A slow aging lion-type creature) did little to answer questions as to the fate of the cast either. Cue the eventual Compilation EIGHT years later, which finally set the record straight.
 * In Vagrant Story (which takes place centuries after Final Fantasy Tactics), various item descriptions mention the Zodiac Brave Story from the first game, naming Agrias, Orlandu and several others as well-known heroes. That means the Durai report from Tactics, containing a true account of what happened during the war, was eventually accepted as historical canon.
 * In Baldur's Gate II: Throne of Bhaal (the expansion pack to the second game), Sarevok, the villain from the first game, can finally find redemption.
 * Akiha's True Ending in Tsukihime is rather bittersweet at best and very ambiguous on whether or not The sequel/sidestory Kagetsu Tohya then had the short story "A Story for the Evening" which follows said ending. It reveals that
 * Any fighting game character who attains their goal will be this. They may spend four games trying to raise that money/defeat that evil bastard/find that lost relative. Of course, the sequel normally reverses this.
 * Sonic the Hedgehog 2006 ends with Sonic erasing the events of the game from history... Except for Silver, who remains living in the Crapsack World of his time, and with his best friend Blaze now living in another dimension. Come Sonic Generations in 2011, Silver is reunited with Sonic & Blaze, and instead of returning to his own time at the end of the game, winds up living in the present with the Bad Future he comes from no longer a possibility. Oh, and he was also Rescued From the Scrappy Heap, too.
 * Actually, the ending of Sonic 2006 has Elise erasing Solaris, the entity that caused The End of the World as We Know It meaning that while we don't know what Silver's future was like, odds are it turned out a lot better than in game. Though Blaze apparently never meets him in the new version.
 * Sonic needs to go through the events of the game to erase Solaris from existance, so the post-apocalyptic wasteland still exists in an alternate timeline in order to avoid a Time Paradox. On top of this, Silver & Blaze in Generations clearly remember the events of the game.

Western Animation

 * Batman Beyond: While The Reveal in "Epilogue" caused a bit of a Broken Base, the episode finally gave resolution to Terry and Dana's relationship, which made them and their shippers very happy.