The cast of Nine and associated tropes for each.
Stitchpunks (counted down from 9 to 1)
"To Save Us"—Voiced by Elijah Wood
The main character of the film and short film, 9 is the final creation of Scientist before his death. A young, spirited and adventurous person, 9 also has vast curiosity which unfortunately leads to the awakening of the Fabrication Machine which previously destroyed humanity and now wants the Stitchpunks' souls. He tries to right his wrongs and becomes the leader of the Stitchpunks.
- The Chosen One: He is the least flawed of the Scientist's creations, so the Scientist chose to entrust him with the talisman.
- Don't Touch It, You Idiot!: And if he hadn't, it really would have made things easier for everyone.
- The Hero
- Hey, It's That Voice!: He's Frodo. And a certain tap-dancing penguin.
- And Spyro.
- Idiot Hero: Varies. He's actually pretty resourceful. However, he can also show a lack of common sense, which proves deadly when coupled with his natural curiosity.
- Nice Job Breaking It, Hero: And how!
- Too Dumb to Live: Or, more accurately, he's too dumb for those around him to live.
- He does grow out of it as things become serious.
- Took a Level in Badass
"To Guard Us"—Voiced by Fred Tatasciore
The largest of the Stitchpunks, 8 is the muscle of the group but lacks intelligence and follows 1 as his bodyguard but also has his only friend. He follows 1's orders loyally and often bullies the other Stitchpunks. Where he lacks brains, he makes up in sheer brawn and is quite strong and daring, wielding a large sword made from a butcher's knife, as well as half of a pair of scissors and a magnet which he uses for... questionable reasons.
- Anti-Hero: Type IV
- BFS: By 6-inch-tall doll standards, anyway: a meat cleaver and half a pair of scissors.
- The Big Guy
- Cool Sword: TWO. A blade attached to a sewing needle and a SCISSOR BLADE.
- Died Happily Ever After: During the funeral scene at the end. He gives off a huge friendly grin before dissipating.
- Dumb Muscle
- Fantastic Addict: He's a little too fond of that magnet.
- Hey, It's That Voice!
- Jerkass / Jerk with a Heart of Gold
- The Quiet One: He says five and a third words in the entire film. 
- Says a few more things in deleted scenes.
"To Defend Us"—Voiced by Jennifer Connelly
The only female Stitchpunk, 7 is an independent and strong-hearted warrior. She left the Sanctuary to hunt down the Cat-Beast and discover the truth of the barren world, something which 1 did not agree with and two have been at odds ever since. Spending a vast amount of time in the wasteland allowed 7 to teach herself how to fight and survive, sporting a crow's skull for a helmet and using a spiked staff and other weapons to fight.
- Action Girl
- Blade on a Stick: Twice. Looking closely reveals that it's actually a craft knife blade tied to a clock hand.
- Hey, It's That Voice!: She's Sarah. And Marion. And Maddy
- Lady of War
- The Lancer: 7 and 5 take turns being this for 9.
- Mama Bear / Action Mom: To 3 and 4.
- Nice Hat / Cool Mask: She wears a crow skull as a helmet.
- Pale Females, Dark Males: She's white, and the palest of all the stitchpunks. It's hinted that her fabric has faded in the sun, though even when she appears in flashback she's a paler colour than 1.
- Samus Is a Girl: Her gender isn't clear until she starts talking, what with the lack of...
"To Lead Us"—Voiced by Crispin Glover
The oddball of the group, 6 is in his own world most of the time, painting seemingly obscure drawings which are actually of the talisman used in the film to bring the characters to life. He is actually an oracle figure, having prophetic visions which he expresses in his drawings; 9 is the only Stitchpunk to believe them, although 2 and 5 express interest. 6 has a unique appearance with uneven eyes, wild hair and fingers made from the nubs of ink pens. Because of his weird appearance and attitude, he is often avoided and ignored.
- The Cuckoolander Was Right: And only 9 believed him...
- Ensemble Darkhorse: One of the most popular characters, with about four lines in the entire film.
- Hey, It's That Voice!: He's George McFly. And Grendel.
- Mad Artist
- Mad Eye
- Mad Oracle
- Madness Mantra: "Go Back to the Source..."
- Room Full of Crazy: He has an entire wall covered in drawings of the MacGuffin.
- Shout-Out: Shane Acker has mentioned in an interview that he is a shout out of sorts to Tim Burton.
- Waif Prophet
- The Quiet One
"To Guide Us"—Voiced by John C Reilly
The "middle man" of the group, 5 is a kind-hearted but fearful engineer, healer and 2's assistant. Shortly after his awakening in the world, 5 was wounded in the war and lost his left eye, and was fixed up by 2 to sport an eyepatch of sorts. He acts as the watch tower guard in Sanctuary as well as the healer and peacemaker. He has strong friendships with most of the Stitchpunks, particularly with 2, 7 and 9.
- Ensemble Darkhorse
- Friendly Sniper: Extremely friendly and kind, but uses a crossbow to snipe at a few monsters. It only works against the Seamstress, though.
- Also, the way he found 9 was looking at the wasteland through a sniper reticle.
- Heterosexual Life Partners: Him and 2, who is his mentor.
- Hey, It's That Voice!: Call him Mr. Cellophane.
- Ho Yay: Buckets with 9 and 2.
- The Lancer: 5 starts out as this, but sort of turns into The Chick after 7 shows up. Eventually, 7 takes over The Big Guy duty after 8 is killed, leaving 5 to pick up The Lancer role again.
- Launcher of a Thousand Ships: Everyone likes to pair him with... EVERYONE.
- The Medic: He's always the one seen patching up the others if they're injured - first 9's shoulder, then 7's leg.
- Mentor Occupational Hazard: In the short film. In the 2009 movie, he's less of a mentor figure and more a sidekick, but he still dies.
- No Sense of Personal Space: It's the 9 drinking game! Take a drink every time 5 clings to 9! You'll die of alcohol poisoning by the end of the film.
- Shrinking Violet: Rare male example.
- The Woobie
- 3 and 4
"To Define Us" and "To Teach Us"
Two mute identical twins, 3 and 4 left with 7 to learn the reason why the world is barren. Moving into an abandoned library, the two catalogued and analysed everything they found and formed an understanding of the city's history. They do not speak but rather communicate via their eyes and physical movements. They have the ability to project images and video clips from their eyes. They don't seem very comfortable outdoors.
- Cute Mutes
- Infant Immortality: Not even this film was going to kill the kids.
- Older Than They Look: They behave like the youngest of the group, despite being the two oldest after 1 and 2.
- Single-Minded Twins
- Viewer Gender Confusion or Ambiguous Gender: While the Russian dub of the film explicitly states that 3 and 4 contain the souls of The Scientist's twin sons, Word of God states that their sex (if they have any sex at all, that is...) is up to interpretation.
"To Inspire Us"—Voiced by Martin Landau
A frail inventor, 2 is a curious and adventurous person and is seemingly fearless. 1 deliberately sent him out into the wasteland to die, believing him to be a threat to the safety of Sanctuary. He is kind, caring, generous and uses the world's scattered remains to build inventions. He is close friends with 5.
- Cool Old Guy
- Hey, It's That Voice!
- Gadgeteer Genius
- Mentor Occupational Hazard: He doesn't get much screentime, but he's still the first person 9 meets, and the one who fixes his voicebox.
- Nice Hat: Really. And yes, that's a candle and a glasses lens fixed onto it.
- Sacrificial Lion: He's nice to 9, then gets grabbed by the Cat Beast, gets rescued, and then immediately gets killed by Mr. Fab.
- The Smart Guy
- Tear Jerker: The funeral scene.
"To Protect Us"—Voiced by Christopher Plummer
The leader of the Stitchpunks, 1 is a dogmatic and cowardly person but asserts his authority over the others and likes to subjugate them but does want what is best for them -- most of the time. He wears a hat, cloak and wields a staff to separate himself from the others. He follows the belief that "sometimes one must be sacrificed for the good of many" which leads to clashes with other Stitchpunks like 7 and 9.
- Anti-Hero: Type IV or V
- Dirty Coward: Not that he's entirely unjustified, but still...
- Famous Last Words: "They left us nothing. Nothing. Why do we have to right their wrongs? Sometimes one must be sacrificed."
- Fan Nickname: The Pope Doll.
- Foe Yay: Inevitably. Fans like to joke about the scene where 1 is clinging (for dear life) onto 9's body after the Winged Beast battle. taken out of context, it looks like he's hugging him.
- Foreshadowing: He said that "sometimes one must be sacrificed for the good of many", and he did end up sacrificing himself.
- Grumpy Old Man
- Hey, It's That Voice!: It's Charles Muntz! And Captain Von Trapp!
- Nice Hat: Its similarity to a bishop's miter earned him his nickname.
- Redemption Equals Death
- Taking the Bullet
- Well-Intentioned Extremist
- The Scientist
Voiced by Alan Oppenheimer
The creator of the Stitchpunks and the Fabrication Machine, and the one who started everything. The Scientist constructed the machine to improve the technology of the world, only for the Chancellor's Chronic Backstabbing Disorder to use the machine to build other machines to wage war on other countries. The machines are corrupted and wipe out life on Earth. The Scientist quickly becomes The Atoner and builds the Stitchpunks to bring life back to the world.
- The Atoner
- Casting Gag: The reason Oppenheimer was cast was because he was related to Robert Oppenheimer, the Father of the Atomic Bomb, and similarly showed regret for creating this destructive force when others used it for... less than savory purposes.
- Heroic Sacrifice: The Scientist intentionally gives his life and soul to bring the Stitchpunks to life.
- Hey, It's That Voice!: The Scientist is voiced by Falkor from The Neverending Story.
- Video Wills: The Scientist leaves a video message for 9 instructing him how to kill the machine.
- The Chancellor
Voiced by Tom Kane
The evil, fascist, Hitler-like Chancellor who used the Fabrication Machine to attack other countries. Boy, was that a mistake.
- A Nazi by Any Other Name
- Evil Chancellor
- Eye Scream: An early draft of the film's story featured a scuffle between the Scientist and the Chancellor in the beginning of the film, ending with both dead and the Chancellor with an inked quill stabbed into his eye.
- Hoist by His Own Petard: His use of Mr. Fab mostly manages to make it angry, leading to the Robot War.
- No Celebrities Were Harmed
- The Fabrication Machine/The B.R.A.I.N
- A.I. Is a Crapshoot
- Alternate Character Interpretation: Is it Ax Crazy or just a scared and angry little kid with a lot of power and no idea what it's doing? Does it try to kill the stitchpunks because it's evil or because it wants a proper soul? The stitch dolls are all made of parts of the Scientist.
- Mr. Fab could be called 0, the first life the Scientist made. And since the Scientist's creations each represent one quality of human nature, with 1 being the most flawed and 9 being the closest to perfection, you could say that #0 is the most flawed because it has no human soul.
- Big Bad
- Cyber Cyclops: Its central core bears a striking similarity to the HAL-9000.
- The Determinator: Nothing is going to stop it from building. Or killing.
- Expy: Of GLaDOS. Firstly, its appearance to GLaDOS is uncanny; it first moves around by swiveling on a giant arm that is attached above and the glowing eye in a sphere is exactly like a more steampunk version of a GLaDOS personality core. Second, it 'attacks' with drones and machines, particularly gun-drones with machineguns, and finally it uses a deadly gas toxin (possibly a nerve gas) for an area of effect attack.
- Fan Nickname: It's Mr. Fab!
- Gadgeteer Genius: It makes robots fast without a lot of materials. It also seems to be good at programming AI.
- Genius Bruiser: ...and it has enough strength to knock over an artillery cannon with little effort. Before it was "upgraded", it broke someone's neck without a second thought.
- Implacable Robot: Even after 5 blows up the factory it still chases them.
- Large Ham: Since it could only loosely be called a spider of some sort, the animators decided to base it's mannerisms on somewhat hammy actor performances, such as Vincent Price.
- Red Eyes, Take Warning
- Sealed Evil in a Can: And then 9 just had to go and wake it up...
- Turned Against Their Masters
- The Cat Beast/CSM
- Cats Are Mean
- Off with His Head: Delivered in spectacular badass fashion by 7.
- Red Eyes, Take Warning
- The Winged Beast
- The Seamstress
- Attack Its Weak Point: It's got a red eye which gets destroyed by 5's crossbow bolt.
- Body Horror: She has the corpse of 2 sewed onto her tail. To make things worse, when she sews up stitchpunks to subdue them, she's pulling those threads through their bodies.
- Evil Genius: To a point. The Fabrication Machine's creations get progressively more intelligent as it continues to design, with the Cat Beast being the most primal and animal-like and the Seamstress being the most cunning.
- Family-Unfriendly Death: She gets ground between two huge cogs.
- Go for the Eye
- Hypnotic Eyes
- Shout-Out: A monster who uses dead friends and freaky lights to ensnare her prey...
- Also, possibly, the Other Mother from Coraline, an earlier work of Focus Features. The Other Mother has an affinity for dolls, has sewing needles for hands, and is very snake/spider-like...
- Or even the scary octopus baby doll from Sid's room in Toy Story. Shane Acker stated that Pixar was one of his major influences, so it's pretty likely.
- Uncanny Valley: That creepy, creepy doll face. Covering a human skull.
- "Quiet!", "He warned you." and "Sub- What?"