3 and 4

3 and 4 is the family ship between 3 and 4 from the 9 fandom.

9 (Short 2005)
3 and 4 are only seen at the very end, when 9 holds a funeral for all of his fallen friends. Given that it's the only threat shown in the short, it can be presumed that they were killed by the Cat Beast some time in the past.

9 (Movie 2009)
3 and 4 were awakened on the same day (August 19th) and have never left each other's side since. They were found by 7 during the Great World War, who then escorted them to 1. 8 lifted the helmet he was holding for protection of the others in order to let them take cover. The group then went into hiding from the machines, being the sole survivors of the war, humanity went extinct.

At some point in the past, the group split into loyalists for 1's paranoia-driven leadership and 7's desire to explore the world they woke up in in hopes of finding a way to get rid of the machines for good. So 7, 3 and 4 went missing, with 1 declaring them as good as dead, at least to him.

3 and 4 resurfaced when 7 takes 5 and 9 to an abandoned library after 2's death and the reawakening of the Machine. She reveals that she'd been hiding the two of them from 1, allowing them to fulfill their purpose to catalogue everything by taking them to a place where they could find as much information as they would like. 7 knows that if anyone knows more about the Machine, it's them. As soon as the group arrives in the library, 3 and 4 take an immediate shine to 9, cataloguing him from head to toe. They quickly leave him alone and then catalogue his makeshift light bulb staff instead. 7 explains the situation to them, due to the twins inability to speak, they instead use their eyes to project a video explaining the Machine's backstory pieced together from newspaper articles and public announcements.

9 tells them about the talisman used to reawaken the Machine, but they just exchange information and shrug; neither of them had seen it before. 9 goes into further detail and draws the symbols he saw on the talisman on a wall, which 5 recognizes as the things 6 is always drawing. Thus they have a new goal of finding 6 and using him to find out more about it, but 7 is completely against going back to 1. She leaves on her own accord, content with the staying in the library where they'll be safe.

5 and 9's attempt to get information out of 6 ends in failure as they are discovered by 8 and brought to 1 to be punished for their disobedience of him. However, an attack by one of the Machine's creations leaves 1's group homeless as the cathedral they've been using as a base burns down. So the group reunites at the library and the twins immediately get along with 6, bonding over the drawings of the talisman. However, an attack by another one of the Machine's creations (The Seamstress) leads to 7 and 8 being kidnapped and taken to the Machine's factory. With the Seamstress using 2's corpse as a component (which 7 previously cut off), the twins attend 2's funeral before they go out with the others to save 7 and 8.

Outside the factory, 9 tells everyone to wait to prepare a trap for the Machine while he is saving the others. He manages to save 7, but 8 ends up killed, 3 and 4 help 5 and 1 prepare the trap, but 5 hesitates when he realizes that the trap would put 7 and 9 in danger. They manage to escape unscathed, believing the Machine to be finally dead for good. The Twins find a phonograph and some vinyls, playing "Over the Rainbow", while goofing off with the others. At one point they try to scare 7 by imitating the Seamstress, but 7 scares them instead and they all have a good laugh about it. However, 5 sees a red light coming from the fog, running to tell the others that the Machine isn't dead, but ends up getting killed by it instead. 7 quickly has to turn 3 and 4's faces around to avoid them seeing the corpse of their friend, the group then hatches a plan to run to a broken bridge and letting the Machine fall to its doom.

However, 6 saw 5 trapped inside the Machine, ranting about not destroying it to 9 and getting killed in an attempt to warn the others. 9 tries to convince 1 and 7 that 6 was right, but 1 insists about the Machine needing to be destroyed, with 7, 3 and 4 siding with him. 9 takes another bit of advice to "go back to the source", being completely isolated from the others, he goes back to the room he woke up in. There he finds a message from the Scientist who created the Machine, addressing 9 by name and telling him that he created all of his friends from pieces of his soul, hoping that they could find a way to destroy the machines and bring peace to this world, showing him how to use the talisman.

9 runs back to the others while they're preparing an attack against the Machine, he tells 7 that the Scientist created them and that he knows how to properly use the talisman now. Though 7 believes him, 3 and 4 take 1's order to fire at the Machine with a cannon, luckily not destroying the talisman in the process. 9 tells them of their plan to sacrifice himself, telling them about the code used to open the talisman in hopes that one of them could stop the Machine after his death. When 9 goes to enact his plan, 1 shoves him aside, allowing for 9 to take the talisman and take the souls trapped in the Machine, rendering it powerless. 7 and the twins celebrate 9 as a hero, but he tells them that he has one more thing to do.

The four of them attend one last funeral, where 9 opens the talisman to free the souls of the fallen. As their souls ascend to heaven, rain starts to fall for the first time in any of their lives. The twins try to touch the raindrops as 9 tells them that this world is theirs now.

Fanon
The twins are fan-favorite characters due to their adorable designs and desires to catalogue everything. Previously, their gender was open to interpretation, they have no voices, neutral designs are only ever referred to as a collective. Fans were ecstatic when screenwriter Pamela Pettler gave her okay to people headcannoning them as non-binary.

Whether it is considered "okay" to ship the twins with each other depends on individual preferences. There's only a single romantic fic shipping them on AO3, almost all other fan content about them seems to be exclusively platonic. People do tend to ship them with the other characters, however. Prior to them being accepted as non-binary, they were often treated as female due to 7 being the only confirmed female character in the cast.

Fandom

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