I've got ten.
Based on the God awful Terminator: Genysis trailer, I've finally compiled the OFFICIAL Terminator timeline/timelines. I know there are things floating around on the internet showing a possibility of split timelines, maybe three or four, but again... I got TEN. If anyone wants to make a graphic, by all means, please do!
A few things before we begin:
I will be referring to Chaos Theory a shitload:
"Chaos theory is a field of study in mathematics, with applications in several disciplines including meteorology, sociology, physics, engineering, economics, biology, and philosophy. Chaos theory studies the behavior of dynamical systems that are highly sensitive to initial conditions -- a response popularly referred to as the butterfly effect. Small differences in initial conditions (such as those due to rounding errors in numerical computation) yield widely diverging outcomes for such dynamical systems, rendering long-term prediction difficult in general.  This happens even though these systems are deterministic, meaning that their future behavior is fully determined by their initial conditions, with no random elements involved.  In other words, the deterministic nature of these systems does not make them predictable.  This behavior is known as deterministic chaos, or simply chaos. The theory was summarized by Edward Lorenz as follows:  Chaos: When the present determines the future, but the approximate present does not approximately determine the future. Chaotic behavior can be observed in many natural systems, such as weather and climate.  This behavior can be studied through analysis of a chaotic mathematical model, or through analytical techniques such as recurrence plots and Pointcare maps." - Wikipedia
Henceforth, I will be using the words "timeline" AND "universe" interchangeably. The idea is each "alternate universe" created by Kyle Reese in the first Terminator movie is a "split timeline" from the original "prime one." As if this wasn't obvious, MAJOR SPOILERS FOR THE ENTIRE TERMINATOR FRANCHISE. *note* I'm not counting the Expanded Universe (i.e. comics, games, books, toy lines, or TV show) as "canon" unless someone can provide an official reason I should.
And here... we... go.
TIMELINE 1: TIMELINE ALPHA THE ORIGINAL 1984-2029
Sarah Connor marries/has (a) child(ren) with an unknown man circa 1984-1991. An unknown company/inventor/researcher creates Skynet, a self aware AI (Artificial Intelligence) for the purpose of controlling unmanned drones and bombers. The chief scientist behind this is also not known.
Skynet, built as a Global Defense System, is put in control of NORAD and becomes self aware circa 2:00 am, August 29th 1997. It launches all of our nuclear missiles at Russia, knowing the Russian counter attack would likely end the civilized world. The world "ends" August 29th, 1997, an event which comes to be known as "Judgment Day." Sarah Connor likely never even hears the word "Skynet" or survives this event. A small percentage of humanity survives and begins a war with the machines, which are learning and evolving at an advanced rate.
John Connor, Sarah's surviving son, manages to lead the human resistance against the machines circa 2027-2029 and capture a time machine. The machines learn the identity of Connor and perceive him as their greatest threat. Realizing they can rewrite history/steal a victor, send a Terminator back in time to kill Sarah Connor. Kyle Reese, becoming infatuated with her picture/stories about her, elects to go back in time to protect her.
TIMELINE 2: THE EVENTS OF TERMINATOR/THE EVENTS OF THE ORIGINAL TIMELINE OF T-2
For a bit of a visual aid, we will give you the players in the following timeline (Timeline 1 doesn't get one, seeing as it happens prior to the events of the first Terminator movie.)
In this universe/timeline, they come to the attention of Miles Bennett Dyson. While Dyson is THOUGHT to be the original mastermind behind Skynet, this likely wasn't the case in Universe/Timeline Prime. The Resistance/Kyle Reese had no idea who he was. They didn't know Cyberdyne was responsible. So, in Universe Prime, it likely wasn't Dyson/probably wasn't even Cyberdyne. Dyson himself proclaims that before his intervening, Skynet would have been "years away/a shittier version" than what he can do. He also reverse engineered a whole bunch of things based on the future technology, non-existent in Universe Prime.
Sound confusing? I'll explain.
If we can say the first instance of chaos theory due to Reese intervening in timeline Alpha caused Skynet's production to speed up/get better, it WOULD explain why John Connor didn't tell Kyle Reese, "btw bro, when I'm ten (or thirteen, depending on the movie monologue), they try this shit again with a super advanced for 1991 prototype. Just a heads up and such." The reason is because without Dyson/future technology, there WAS no second strike/no T1000... but wait Marty, cause this shit is about to get really... heavy.
Remember the title of THIS timeline? "the events of the ORIGINAL timeline of T-2"
Based on facts, lines from the movie (and third movie), reasonable speculation/assumption, and of course that lovely little "chaos theory," in the ORIGINAL timeline of Terminator 2 (John Connor from Timeline 2's childhood 1994), the following events LIKELY transpired:
- Sarah Connor is put into Pescadero Mental Hospital circa 1990 following a conviction for blowing up a factory "or some shit" - (John Connor, T2)
- John Connor is put into foster care circa 1990 - (T2)
- Miles Bennett Dyson completes his prototype of the first running version of what will one day become Skynet circa 1993/4 - (T2 Ultimate Edition deleted/added scene)
- Miles Bennett Dyson is NOT killed in this timeline, as the T101 would have also had detailed files on his death/the end of the movie prevents the future (or so we think) - (T101, T2)
- Cyberdyne systems is NOT blown up as per the dark future still happening - (T1/T2)
So... what happened in the future to change all this? Ready for it to get heavy?
Facing annihilation from the humans in 2029, but having the strongest version of Skynet/prep time from Dyson's involvement, the machines send an advanced prototype into the past to try to kill John Connor. Even if "5 seconds" pass in 2029, the T1000's involvement in the past would be known/felt instantly, and since we've never seen a living human experience the creation of a new timeline/tangent universe... it's impossible to know how this played out for 2029 John Connor.
IMPORTANT: We also know the T1000 is NOT successful in wiping out John Connor, as he lives through this event, goes on to 2029, and still is able to do the whole Resistance leader/timecop thing. Therefor, we can infer:
What "likely" happened back in circa 1994:
This date (give or take the one week the movie plays out over) is chosen because John is seen as vulnerable without Sarah - (Sarah Connor/T101, T2).
It's the date the first Skynet Prototype is completed. (T2 Ultimate Edition deleted/extended scenes)
A Terminator, unable to find John Connor, would look for his next of kin/friends and family as the first T101 did when trying to kill Sarah in Terminator. (T1)
A Terminator (yes, T1000 is also just called a "Terminator") with no clue where to go after assuming it failed its mission, would likely assimilate Dyson/Cyberdyne staff as a logical next step. (T2)
It is the date John Connor meets his future wife and her very important father in the original T2 timeline. (T3 - info that could have been extracted/learned by machines by 2029)
Being as chaos theory caused a dark ripple into the future after the events of T1, the timeline is changed enough for them to have the T1000 and send the second strike. The humans have no captured/reprogrammed T101 yet. This is reinforced by Reese not knowing who built Skynet/caused the war, when it should be common knowledge to the Resistance. This means they changed something that puts Dyson at the head of the line, his involvement likely leading to a T1000 being created at all.
IMPORTANT: Nothing that we see in T2 concerning the T1000 would change until the intervention by the "friendly" reprogrammed T101, because in THIS timeline, there was NO protector T101. When the T1000 can't find John, it kills his foster parents as it does in T2. The next step, just like the movie, is Pescadero. In this timeline, it absolutely KILLS Sarah Connor and then does fuck all until Judgment Day, as it cannot self-terminate or find John Connor.
This "change" is felt immediately by John Connor in 2029, as his memories suddenly change from a life with his mother to his mother being killed by the machines (inference/Flashpoint/Flash Rebirth DC comics; X-Men Days of Future past/House of M/Age of Ultron Marvel Comics).
TIMELINE 3: THE EVENTS OF TERMINATOR 2 (FROM THE MOVIE ITSELF)
The humans have captured/reprogrammed the T101 and send it back in time with not one, but TWO missions:  Protect John Connor - (T101, T2).  Protect Sarah Connor (inferred by the T101/everything I've written). Wait... what? That Terminator didn't "care" about Sarah at all! Show your work!
I got you.
The humans in 2029 send the T101 back NOT to protect John (he already lived through the T1000 attempt and therefore was in no actual danger) but to keep Sarah alive/try to change the future... again... back to the... nevermind... THIS is why the T101 never questions the order to rescue Sarah, despite it putting John in danger. It is also why it repeatedly saves her life before and after being reprogrammed, despite not having any reason to do so.
IMPORTANT THEORY THAT I THINK PROVES ITSELF... Sarah Connor (the one from Timelines 2 and 3 for argument's sake) knows she IS supposed to be dead by 1997/2029, likely killed by "the machines/Skynet" but not necessarily "Judgment Day" itself, more likely "now" in 1993/4.
Sarah has a dream of Kyle Reese (sadly cut from the original movie), in which he tells her John is in danger. Sure it could be PTSD or coincidence, but if Chaos Theory can cause ripples (thus making the bad stuff happen), maybe it could also cause a warning/deja-vu ripple. Because, even in Timeline 3, Sarah WAS still trying to escape Pescadero when the T1000 kills her, as the T101 had not yet intervened. - (T2 Ultimate Edition extended/deleted scene)
Sarah is able to take extreme measures to facilitate her escape because she firmly believes that "everyone" (not named John Connor and biologically related to her) is "already dead," herself included. She also has gotten the "Reese Warning" at this point/had several dreams of dying in Judgment Day. She is now trying to get out and not in three years, because she believes there's imminent danger. - (Sarah Connor, T2) Sarah knew the T1000 would come for her. The T101 killed her friends/roommate and family (T1). After reuniting with her son, she first expresses the belief that there are different timelines/alternate futures by reacting to John's presence. She scolds him for coming to rescue her, saying he is "too important." She knows John was supposed to survive the war but there's no mention of her. By Reese's time, she's a "legend" with no further mention.
"Got the future by the balls/we're making history right now" - (Sarah/John/Dyson, T2)
Sarah's monologues throughout T2 are very telling to the indication of alternate timelines. However, given that Sarah probably put all these pieces together, I think she also was speaking about having a second chance at life, especially given the opening:
"Three billion human lives ended on August 29, 1997. The survivors of the nuclear fire called the war Judgment Day. They lived only to face a new nightmare, the war against the Machines. Skynet, the computer which controlled the machines, sent two terminators back through time. Their mission: to destroy the leader of the human Resistance... John Connor. My son. The first terminator was programmed to strike at me, in the year 1984, before John was born. It failed. The second was set to strike at John himself, when he was still a child. As before, the Resistance was able to send a lone warrior. A protector for John. It was just a question of which one of them would reach him first..." - (Sarah Connor, T2)
We don't know at which point in time she is speaking these words, but it's likely AFTER the events of T2. Later when going to Cyberdyne, she says, "The future, always clear to me, has become like a black highway at night. We were in uncharted territory now... making up history as we went along." And of course the ending: "The unknown future rolls toward us. I face it for the first time with a sense of hope, because if a machine, a Terminator, can learn the value of human life... maybe we can too."
While they had every reason to think they prevented the dark future, for the first time she has hope about seeing tomorrow. August 29, 1997 comes and goes with no problem.
TIMELINE 4: THE EVENTS OF TERMINATOR 3 IN ITS ORIGINAL TIMELINE
Let's introduce some new, some changed, characters into the timeline...
By 2029, the dark future still exists and machines have taken heavy losses. Unable to find John or Sarah in the early 2000s, they send a TX (advanced Terminator) back to eliminate his lieutenants and future wife. She is sent to the dawn of the new Judgment Day, likely to turn the tide of battle in the machines' favor during the earliest days of the war.
In the original timeline of this film, none of these people died before 2029 if at all, except 2029 John Connor (by the T101). What is most important here is Kate's father having survived/becoming a target, meaning he WAS around for John's early years.
TIMELINE 5: THE EVENTS OF TERMINATOR 3 (RISE OF THE MACHINES)
"The future has not been written. There is no fate but what we make for ourselves. I wish I could believe that. My name is John Connor. They tried to murder me before I was born. When I was 13, they tried again. Machines from the future. Terminators. All my life, my mother told me the storm was coming. Judgment Day. Connor! The beginning of a war between man and machines. Three billion lives would vanish in an instant. And I would lead what was left of the human race to ultimate victory. It hasn't happened. No bombs fell. Computers didn't take control. We stopped Judgment Day. I should feel safe... but I don't. So I live off the grid. No phone, no address. No one and nothing can find me. I've erased all connections to the past. But as hard as I try... I can't erase my dreams... my nightmares. I feel the weight of the future bearing down on me. A future I don't want. So I keep running... as fast as I can. Anywhere. Nowhere." - (John Connor, T3)
^ Another example of the chaos theory ripple effect to give off a warning for John to stay off the grid due to a temporal disturbance from:
In 2029, Kate Brewster avenges/hopes to avenge John's death by sending back the reprogrammed T101 to protect them in the past/present. The TX goes back in time to kill the lieutenants and kills several, including Kate's father/John's mentor/military arm during the early years. Judgment Day happens in 2004 and John Connor becomes the first leader of the Resistance.
Wrap-up before Salvation and Genysis: Being that Kate's father was one of John's lieutenants/important father figure with military experience, for the John Connor of timelines 2-4, his status working with Skynet and as a General probably saw John on a much different path. It's not likely he was important enough to make the "kill list" in Salvation/any of that shit even happened in the 2018-2029 of those timelines. They probably never even encountered Marcus, Reese wasn't a prisoner and hunter/gatherer, etc.
Welcome to the game, Marcus, hunter/gatherer Kyle Reese, and Dr. Kogan!
Marcus learns from Skynet, which assumes the form of Doctor Kogan on a screen, that he was created in order to lure John to the base. When the Resistance launches its attack, John will be killed, achieving the goal Skynet had failed to accomplish so many times before. The radio signal the Resistance's plan depends on is a ruse, and Skynet uses the signal to track down and destroy the command submarine with the Resistance leaders aboard. (Terminator: Salvation)
Marcus was created (circa 2018) BY Skynet, with the future knowledge of John Connor being the ultimate enemy, something they couldn't possibly know until 2020ish ('cause let's face it, he's still done FUCK ALL by 2018). This completely backs up the theory of the changes from Timelines 4 and 5, because Skynet FINALLY now knows a "when and where" John Connor will be and how to appeal to his "stupid human emotions." Remember, he likely never met Marcus in Timeline 4 because there WAS NO MARCUS.
This means the TX had the foresight from the future to FINALLY leave Skynet an "in case this all goes to shit" contingency box that says, "John Connor lol kill him tho for srs," something the machines never once thought to do previously (because it's not like they'd fail or anything). In Timeline 4, the Resistance leaders on the sub are obviously NOT killed on the sub... they not only kill them, kill Kate's father, kill several of John's lieutenants (changing GOD knows how many victories), but they also FINALLY manage to kill John... twice. Timeline 4 is easily Skynet's most successful. As much as it pains me to say it... the combination of the TX and original T101 prove to be their best... assets... wow that hurts just writing.
TIMELINE 6: JOHN TRIES NOT TO BECOME A PARADOX (EVENTS OF THE FILM SALVATION)
READY FOR SOME MORE CHARACTERS?!
THIS Kyle Reese is already a COMPLETELY different person. John Connor from Timeline 2 onward is a fucking moron. Despite GLARING evidence of split timelines, alternate futures, his mother figuring it out, his original/true father figuring it out, his pet T101 figuring it out, his angry pet T101 that doesn't like him very much (like when your girlfriend's cat dies and you mutually don't like each other) figuring it out, and yes, even Skynet FINALLY figuring it out by engineering Marcus and THEN rubbing it in John's face....
HE STILL DOESN'T GET IT.
So naturally, he sends Kyle Reese back in time.
IMPORTANT: Kyle Reese and why this matters for Salvation/Genysis;
The Kyle Reese of Universe Prime (that's the one we meet in the first flick aka Michael Biehn) is probably a completely different person from the Kyle Reese in Universe 2, and has altogether ceased to exist by Universe 3. NOTHING that John did in Salvation mattered to the past in terms of keeping himself or Reese alive, because it would just create yet another universe.
Sure, we could have speculated the plucky kid (Hunter/Gatherer) would grow up to become badass Michael Biehn and the events of Terminator would play out. It's not like they had another movie that would PROVE everything I've been prattling on about. Chaos theory "obviously" works in reverse too. Same Reese, same John, paradox, etc. and then... THANK YOU (ONLY time I will EVER say that) Terminator Genysis!
But I'm jumping the gun a bit here...
TIMELINE 7: EVENTS OF TERMINATOR: GENYSIS TRAILER IN ITS ORIGINAL TIMELINE
Finally (almost done)...
Machines send a Terminator to kill a much younger Sarah Connor circa 1973-1980. It fails due to a future Resistance sending an old man Terminator, which they just "had" for some reason.
TIMELINE 8: THE EVENTS OF THE TERMINATOR GENYSIS TRAILER "REESE"
The (circa) 2029 Resistance sends Kyle Reese to carry out the events of the first Terminator. He's beaten to the punch by the old man Terminator... which they have also send back in time, which means....
TIMELINE 9: THE EVENTS OF T:G TRAILER "SARAH AND OLD MAN TERMINATOR"
Despite what an incredibly stupid and... no, stupid covers it... plot point of the "old man Terminator," is what most people are overlooking. They wouldn't have sent Reese if he didn't need to go/they didn't expect or know about the old man Terminator, which they themselves sent... which means they sent him from a later point in the 2029/future (either from 5 seconds after Reese left or any point until the end of the Resistance, it doesn't have to be sent by John or Kate), BECAUSE something goes horribly wrong when only THIS Reese goes. I can speculate but our heads hurt enough already (or I'll wait for the movie to be on dvd because there's no way in hell I'm seeing this in theaters).
TIMELINE 10: SPECULATIVE FUTURE GOING FULL CIRCLE/REVISITING SALVATION - THE SPECULATIVE EVENTS OF TERMINATOR GENYSIS
While we can speculate if protecting Sarah by the "Salvation Universe Reese" or "knocking up Sarah by the Salvation Universe Reese" is what ultimately fails, calling for the old man Terminator to be sent back, the only real variable that has changed in the future timeline is the "Marcus Plan."
Up until the point of the Salvation timeline, John Connor never had a mother who in turn, had an old man Terminator or was targeted before 1984. The only thing that changed was the Marcus Plan, Skynet's ace in the hole with an absolutely uncertain future, which means Skynet REALLY learned and had a contingency... which was itself a contingency for the T1000/Cyberdyne having been blown up. Say what you will, but DAMN, Skynet is optimistic and resilient.
So my ultra cliche speculation is that JOHN CONNOR still does NOT realize, "holy shit... chaos theory/alt timelines lol," and has to revisit Marcus saving him. He then has to sacrifice himself to save the lives of his mother and father in the 80s... even though these are the mother and father of a different John Connor. I'm betting at that point, Arnold sacrifices himself... again.
A. The clear "villain" of the franchise is the Kyle Reese of timeline/universe alpha. He endangered the entire future by intervening in Sarah's life, knocking her up with the wrong John Connor that she had to MAKE become the great leader (that at the end of Salvation, I still have yet to see him become) because he sure as shit wasn't born one. Reese was the first to figure out the "no fate" thing, meaning he KNEW he was jeopardizing the future/his own existence/ the hopes of the Resistance.
B. Sarah (universe/timelines 2-3) knew/expected she was going to die circa 1993/4, likely by a Terminator's hand. She also completely figured out both chaos theory and the "no fate" thing.
C. Every iteration of John Connor from universe/timeline 2 onward was NOT the badass resistance leader from Terminator (the first movie). However, under the direction of Kate's father, we ARE to assume Eddie Furlong's John Connor turns into the badass Connor from the T2 intro.
D. Every iteration of John Connor from universe/timeline 2 onward is in HORRIFIC danger.
Timeline 2 John Connor is targeted by the T1000 that kills Sarah and his foster parents. He is likely taken in by General Brewster after the multiple murders/him hanging around the general's daughter/the General having an association with Cyberdyne (what will one day become Skynet). None of these people might have ever crossed paths in Timeline Prime, so this John Connor is thrown entirely to the wolves with no Sarah or Reese to guide him.
Timeline 3 John Connor was in mortal danger the second he decided to save Sarah from Pescadero. By the end of the movie, he has suffered severe emotional trauma, finding out he left his mother to rot and she was telling the truth, losing the only father figure he ever loved... even if he was made of tin. Not to mention, the god complex of literally changing the future/the fear of "what if we didn't." It's enough to turn anyone into Nick Stahl - also without Sarah but still with the General's influence.
Timeline 4 John Connor was Nick Stahl. Yikes.
Timeline 5 John Connor was Nick Stahl without his lieutenants and father figure/military arm General; people so important to John's cause, that Skynet settled for wiping them out.
Timeline 6 John Connor is the first one that Skynet is able to actually kill (unless you count the one from Timelines 4 and 5, but that was at a later date).
Timeline 7 John Connoer-onward has still learned nothing and is winging it, ultimately making things worse and worse in each timeline.
The TX was easily the most successful endeavor by Skynet. She's also the ONLY Terminator who not only accepted but anticipated failure... repeatedly.
In closing: Skynet, a machine, killed "three billion people" - (Sarah Connor, T2)
*via tactical nuclear strike for strategic reasons like "people suck lol." Now to be fair, the ACTUAL world's population in 1997 was 5.8 billion, but it's still nothing compared to:
Kyle Reese of Timeline Prime's actions led to the deaths of:
-Six point FIVE billion (the world's population circa 2004, the second Judgment Day)
-Sarah Connor (Timeline 2)
-Sarah Connor (Timelines 3-7)
-Every person the T1000 kills; Miles Bennett Dyson (Timelines 2-7)
-Every person the TX kills (Timelines 4-7)
-Every person Skynet is able to kill due to Marcus (Timelines 6-7)
-John Connor - T101 circa 2029 (Timeline 4)
-John Connor - T101 beta (Timeline 6-10)
Kyle Reese had one mission, to PROTECT SARAH CONNOR, and by extension John Connor. In every universe that follows, his involvement gets them both killed.
Kyle Reese majorly fucked up time 'cause he just wanted to get laid.