56

56 is the slash ship between 5 and 6 from the 9 fandom.

9 (Short 2005)
5's character had already been semi-established in the original short (though with a few stark differences), 6 was just another Stitchpunk who died before the short's story started. After 5's death, 9 prepared a funeral for all of his fallen friends, allowing for 5 and 6 to move on.

9 (Movie 2009)
As explained by 1, 5 and 6 were two of the eight Stitchpunks who comprimise the only survivors, having managed to hide from the machines created by the Fabrication Machine to kill all of humanity. Before the movie began, 5 and 6 were indoctrinated into 1's belief of nobody being allowed to leave is cathedral, else they are pronounced dead. Three of the eight cut themselves off of 1, leaving 5, 6 and 2 at the mercy of 1 and his enforcer, 8.

When 9 enters the picture, having been awakened that day, 2 goes missing by being captured by the Cat Beast, who also stole 9's talisman the Scientist who created the Fabrication Machine left behind for him. 5 saves 9 and is the only one of the present Stitchpunks to treat him with kindness, 6 only watches him from afar while drawing strange symbols.

When 5 and 9 defy 1's order behind his back to save 2, they reunite with the defector 7. However, due to 9 foolishly putting the talisman into an outlet, awakening the Fabrication Machine and getting 2 killed when he tried to stop it. After a moment of rage and grief from all parties, 9 asks 7 about the Fabrication Machine, so 7 takes to a library where she hid the twins 3 and 4 from 1. There they find out more about how the Machine was created as a tool for invention, but was forced into created weapons of war by an evil Chancellor. 9 get no answers about the origin of the talisman, but him drawing the symbols he memorized led to 5 recognizing them as the symbols 6 is always drawing.

Though 7 advices against going back to 1 in hopes that 6 could help them, 5 and 9 try to sneak back just to look at 6 drawings in hopes of finding a clue. They are discovered by 8 who takes them back to 1. Disappointed in them for disobeying him (along with reawakening the Machine and getting 2 killed), 1 orders 8 to subjugate them, including 6 which 8 does by taking 6's drawings away. 6 wound up being catatonic during a suprise attack by the Winged Beast (a creation of the Fabrication Machine) hunting down 1, but is lucid enough to team up with 5 to help kill the beast by tying a rope attached to it during the fight to a propeller and activating it, tearing it into shreds.

Unfortunately, this causes a fire to start, burning the cathedral and making it unlivable, leading to 1 taking 8 and 6 to the library while 6 tries to save his burning drawings, but soon realizes that it's hopeless and runs after the others. Though things seem quiet at the library, the Fabrication Machine prepares another attack by using 2's corpse, some string and a porcelain doll, it creates a new machine called "The Seamstress" with the power of using the flickering light of 2's eyes to petrify the Stitchpunks, then using needles and string to tie them up to deliver them to the Machine. During the attack, 7 manages to cut 2's body off of the monster, but gets captured herself along with 8. Before going after them to save them, they find 2's body and give him a viking funeral, with 6 being shown to cling to 5 for support.

When they reach the factory, 9 tells 5 to stay behind and prepare a trap for the Machine with the others while he goes in to rescue 7 and 8. 8 gets killed before 9 could reach him, but he manages to save 7, who in turn saves him when 1 activates the trap prematurely. Believing that they have won, the remaining group finds a phonograph and celebrates their victory by listening to "Over the Rainbow". 5 and 6 have the most fun with each other, but the fun won't last.

5 discovers the Fabrication Machine coming towards them through the fog, with 6 being one of the Stitchpunks to witness 5's soul getting sucked out by the talisman. 6 is the only one who got a clear look at 5's soul inside the Machine's eye, correctly guessing that 5 along with 2 and 8 are trapped inside the Machine. He frantically runs up to 9 and tells him not to destroy the Machine or he will doom them for good, but when 1 hatches a plan to drop the Machine down a run-down bridge, 6 becomes careless and gets dragged down with it. Before also getting his soul sucked out, he tells 9 to "go back to the first room".

9 is then determined to save the lost souls, rebelling against 1's new ideology of destroying the Machine before it takes one more soul. He does as 6 told him and finds a message from the Scientist, telling him that he created all of them with pieces of his own soul, using the talisman, showing him the combination to open it and use it properly. He goes back to the others to tell them of his plan to sacrifice himself so another one of them could grab the talisman and defeat the Machine, but 1 has a last minute change of heart and sacrifices himself instead. 9 then uses the talisman to suck all five claimed souls out of the Machine, draining it of its power in the process. Along with 7 and the twins, they open the talisman at a mass funeral for the other five, watching them gently float towards the horizon, causing it to rain for the first time.

Fanon
56 is the most popular ship for both characters, not counting OCs. Tellingly, they're popular to ship individually because they happen to be people's favorite characters and the fandom seems to be in agreement that they both deserve to be happy. Most fanwork featuring this ship tends to be canon-compliant, with all the implications of them still dying at the end of the story.

Fandom

 * FAN FICTION