As this is a Wild Mass Guessing page, beware of unmarked spoilers for Fight Club.
Tyler Durden and the Narrator are Francois Dillinger and Nick Twisp (respectively) from Youth in RevoltIn Youth in Revolt, the mild mannered Nick Twisp creates an alternative persona that is everything he wants to be, and leads him to commit crimes that including major property damage. The course of events that Tyler Durden initiates is similar, if on a larger scale. He is also a similar creation: he is everything the narrator wants to be. Is it so hard to believe that Nick Twisp lost track of the fact that his illusion isn't real, leading him to cause even greater destruction later in life?
Project Mayhem wasn't as widespread as the Narrator was lead to believe.Tyler led him to a station that had several members of Project Mayhem who were on watch for him trying to come in and start asking questions or talking about Fight Club, as well as to a vacated credit building with a mostly-fake bomb, like he said he would do with the wires. It worked because the Narrator wasn't expecting it, or because pulling any wire would have defused the bomb and he wasn't even trying then.
Tyler Durden is, in fact, a vampire.
The narrator is the son of a (deadbeat) vampire father and a mortal mother.Tyler Durden is the vampire half of him that only needed sufficient catalyst to push through.
The punishment for interfering with Project Mayhem has to do with Bob.The beginning of the film sets the scene in the testicular cancer group as very emotionally important to the Narrator, who probably mentioned or even suggested it offhand to Tyler during one of his rants (being more punishment than killing them, after seeing how it messed with Bob and killing someone, while it would shut them up, would not teach them not to ask about Project Mayhem).
The narrator is Calvin from Calvin and Hobbes(spoiler for childhood-destroying Poison Oak Epileptic Trees) This is also seen at the WMG page for the series mentioned, and it is written about thoroughly ((and convincingly) in this essay.
The Narrator is Jack NapierThink about it, Tyler Durden's goal in life is to cause pure chaos. He also knows how to makes explosives from regular household materials. What really set this for me, is the scene when Tyler gets beaten down by the bar owner and then jumps on him and laughs at him. Also when you see the place they bombed and Tyler painted a smile on the building. That's when I knew that Tyler really was Jack beginning to become The Joker and Fight Club is an alternate take on his beginning. Tyler may have been beaten at the end of the movie but there's always a chance he'll come back. Alternatively, The Narrator is Bruce Banner, and the part of his mind that is Tyler Durden is what causes him to become the Hulk during the accident.
The Narrator's real name is Terry Ludden.It's an anagram. We've all seen it before, so why not?
The Narrator's real name is Tyler Durden.It's what he tells everyone his name is, including Marla and the rest of the Club. He doesn't recognize it as his own name when Idealized Tyler tells it to him because of the very same psychological problem that caused him to generate the Idealized Tyler persona.
The Narrator's real name is Rupert.What? Why are you looking at me like that?
Marla is a trans woman.No particular reason, except the lack of testicles.
The Narrator is one of the awake.He has chronic insomnia, and his madness talent is convincing people to listen to him. Tyler's what happens when the player added Madness Dice once too often.
The Narrator's real name is JackBecause being Jack's wasted life (and other stuff) is how he feels - in that particular moment - filled with that sensation (and the other ones).
The Narrator's real name RUDELY TRENDIt's an annogram of Tyler Durden
Tyler started out genuinely trying to enlighten people.As he/Jack got nuttier, he decided the awakening needed to happen faster . . .
Mark is The Narrator's son.
Tyler Durden is a real personThe Tyler from the plain is real, and the Tyler the narrator made is based off of him
Tyler Durden/the Narrator is the Joker from the Dark Knight.In the novel, the narrator shoots himself in the opposite cheek from the one that has a hole in it, and says that it gave him a "jagged smile from ear to ear." And now we know how the Joker REALLY got those scars.
Most of the members of the Fight Club are just as imaginary as Tyler Durden.Because doesn't seeing them everywhere sound a bit too much like pure paranoia?
The Narrator legitimately has DID, and Tyler isn't the only one of his alters.Tyler is just the first one he notices because he's the first one that went out of hand. People with DID generally don't just have one alter, but many. He probably had some sort of childhood trauma caused by his father, which is why Tyler hates their father but The Narrator remembers him being away all the time.
Marla is one of The Narrator's alters.We never see anyone but Tyler and The Narrator talk to her, and she's just as mysterious as Tyler is. The reason The Narrator doesn't realise this is because 1) he has a horrible mental disorder and 2) she never takes over.
None of this actually happens, and The Narrator is in an asylum.Certainly believable, considering.
Tyler Durden is a Dark Passenger.
Mugi is Tyler's Daughter.He sent her off to live with some family in Finland, family who later moved to Japan. Just look.
Project Mayhem became the League Of Shadows and The Narrator/Jack/Tyler Durdanis Ra's Al Ghul . Think about it, a terrorist group that destroys cities that have been amassed in both weapons technology, and material goods. They use both military tactics, ninjitsu and martial arts during their goals. To top it off their leaders have two aliases Jack/Tyler Durdam - Ducard/Ra's Al Ghul. Ducard remarks that he had a wife that perished, that could have been Marla Singer. He uses his calmer side to appeal to Bruce Wayne and Mentor him. But when Bruce burned his house down and left him for dead, The Ra's Al Ghul side took over.
Tyler Durden is Jeffrey Goines from "12 Monkeys", and the events of the movie are just a dream.A scarily plausible one, really. Jeffrey is spastic, hyper, but ineffective for most of the movie. Of course he would create a dream self that is himself, but SO much cooler. The movie ends with his death because he has to wake up. As for similarities between the two: Both share their opinions on consumerism and the current decline of society. There is a rumor (stated by Bob to The Narrator) that Tyler was "born in an asylum and only sleeps one hour a night". In "12 Monkeys" you see that Jeffrey hardly ever sleeps. They also tend to talk the same way (though Tyler is much more calm and controlled), and The Narrator can easily be seen as a foil whose only purpose is to make Tyler look cooler by comparison. Notice that Tyler wins in the end, even though he has to "die".
Bob's death is a reflection of how he was never cut out to be in Tyler's armyTyler's recruitment method focused on the recruit remaining on his porch, despite abuse. After Durden told him to fuck off the first time, he went to walk away, and only stayed due to the narrator's interference. He was never cut out to join the army, which is why he was the only casualty.
Fight Club eventually broke into the online world......and became Anonymous.
Tyler is, indeed, a real person. The entire part of the movie after he disappears is Jack's descent into madness.Consider how betrayed and shocked Jack is that Tyler is gone. That such an integral person to the house could up and leave without warning. And consider also that only after this happens do things start getting really, truly strange. Jack just went insane, and possibly is lying on a sofa in the house, though if Tyler ever comes back he may snap out of it. Maybe.
The Narrator/Tyler Durdeneventually combines both of his [[spoiler: personalities into one Super-personality which leads to him becoming V from V for Vendetta
The Narrator is Todd from Squee and Tyler is Shmee.
Fight Club takes place in the MatrixWell, you know — all movies that came out in 1999 take place in the Matrix, don't they? Well, except Dogma.
Tyler is a rogue tulpa.Specifically, he's the manifestation of all the rage and frustration of all the men who joined any fight club ever. As the generation of "Slaves with white collars" came of age, with "no great depression, no great war", they felt largely emasculated, since they had no conflict or struggle with which to identify, nothing to prove their manliness, if only to themselves, thus resulting in Tyler's ultra-masculinity. Jack's own addition to this frustration finally brought Tyler into existence, though only temporarily, since he could only take over when Jack was sleeping. Any time Jack watched Tyler do something, he was out cold, and the tulpa was in control of his body. Tyler's direct interaction with Jack made him aware of Tyler's existence solely as a thoughtform. By symbolically killing Jack, Tyler was seeking to have a permanent physical presence in the world.
The entire movie is a hallucinationNone of the movie actually happened. The entire Project Mayhem is as imaginary as Tyler. A lot of the movie seems a bit implausible, like with how omnipresent Tyler's army is, and how the narrator was able to travel across the country setting up Fight Clubs without realizing it (you'd think he'd realize all the days that vanished). The biggest clue though, is his knowledge of explosives. If Tyler isn't real, the narrator never learned how to make explosives. If he can't make explosives because he doesn't know how, then the explosives in the movie can't be real. The movie is actually the narrator fantasizing about lashing out at society, and ultimately rejecting it in the end.