Some DB Time Travel/Timeline Questions

[Analytical Delusion]

(1) We know new timelines are created when someone goes back in time. Are they created when someone who went back in time, returns to his/her own time? i.e. Trunks and Cell created new timelines when they went to the past, but were future timelines created in which they never returned?

(2) Was a new timeline created when Trunks returned to the past a second time to help Goku & co.? Or since he had already been to that timeline, was there no change (Herms noted in another thread, that even though 3 years had passed in the present, that Trunks likely had only waited 8 months for the time machine to charge for another return trip; EDIT: I do understand there is some good timeline discussion there, but didn't want to bump it with my questions since it's several years old)?

(3) So Cell traveled back to the past, a year before Trunks had arrived to warn everyone about the Androids. After the CG, we see Trunks preparing for another return trip, before he takes out Cell. Would it make sense for him to travel back to that same year Cell's machine was programmed to and create another timeline, even if (Goku's death aside) everything was resolved in the timeline he visited originally (the timeline that is the focus of the manga)?

(4) How the heck did Cell get to the same timeline Trunks traveled to, without creating a new timeline that Trunks never visited (even if he arrived a year before Trunks)?

Where I'm at right now:

(1) New timelines are not created when someone goes back in time.
Reason: There is no paradox, since time in the timeline from which someone is traveling does not need to be overwritten.

(2) I'm split on this.
Reason; I don't know if a paradox is created, since the timeline is already familiar with Trunks. The fact that it's not a 1-to-1 passage of time (since 3 years passed in the present timeline, and 8 months in Trunks's timeline) makes things weird. Gun to my head, I'd say no timeline is created since I don't have a strong conviction.

(3) No clue right now. I'd like to believe Trunks just returned to the main timeline, after killing the Androids and Cell in his time.
Reason: As I said above, I don't think it makes much sense for him to create a new timeline by heading back that far.

(4) I have no idea.
Reason: This makes no sense to me, at all. How is the new timeline created when Trunks kills Cell, and where does it go? This is a paradox since Trunks shouldn't know about Cell, but from where does the new timeline sprout? Is it just split off from that current trip in his timeline, or is another timeline created out of nowhere, or something else entirely?

EDIT: For the record, here is a link to a translation of the page (by one of Kanzenshuu's members), but I don't believe that it answers my questions (and not to be difficult, but I'd prefer to arrive at a solely manga-informed explanation, if it's at all possible; for instance, I have trouble believing/understanding the remote destroying 17/18 as a paradox creator).

[Zephyr]

I subscribe to two main ideas for how time travel works:

1. Whenever someone travels to a point in the past for the first time, this creates a new splinter timeline.

2. "Return trips" are possible. Trunks can return to his future without creating a new splinter timeline. He can also return to a timeline he'd already created, so long as he doesn't travel to a point prior to the timeframe in which the new splinter timeline had been created.

With those in mind, answering your questions:

(1) No new timelines were created by Trunks returning to his future.

(2) No new timelines were created by Trunks traveling back to the timeline he'd created.

(3) I assume you're talking about the whole "Trunks wanted to go back and tell everyone that things are fine" prior to having told them about the Androids? The easiest explanation I have for that is that Trunks wasn't planning to go to that point, Cell accidentally hit something which made it go to that point in time. That's contradictory to the explanation given in the guidebooks, but this one makes more sense to me.

(4) I've always assumed that in the initial timeline that Cell created by traveling back in time, he died in hibernation for some reason. This caused Trunks' future to still occur as usual in this fork. So we have a second instance of Trunks' future, from which Trunks travels to the past. Only, in the past of this timeline, there's already a dormant Cell. Butterfly effect in full swing, this causes Cell to not die in hibernation, allowing him to wake up and set the Cell Games in motion.

Or to better help illustrate my interpretation of it all:



Purple Line:
Goku dies due to his heart condition, Artificial Humans essentially kill everyone else, Trunks travels to the past, returns with a remote control that allows him to defeat the Artificial Humans, and finally Cell steals his time machine.

Red Line:
Trunks arrives in the past and warns of the impending Artificial Human threat. They are eventually defeated via a remote control, built from blueprints found in Gero's lab. Trunks takes this remote to the future with him.

Blue Line:
Cell arrives in the past and begins his hibernation. Goku dies due to his heart condition, Artificial Humans essentially kill everyone else, Cell dies during hibernation, Trunks travels to the past, and returns with new-found strength. He utterly defeats the Artificial Humans, as well as this timeline's Cell, on his own.

Green Line:
The main story we see. Trunks arrives in the past and warns of the impending Artificial Human threat. Cell survives his hibernation. The heroes train, Cell achieves perfection, and the Cell Games are held. Trunks returns to his time with new-found strength.

Spoiler:

Those black lines don't mean anything. MSpaint didn't do the best job of shrinking the image down.

[Analytical Delusion]

Thanks for the response. You're correct about question 3, that is exactly what I was referring to there. I guess attributing the year selected, which would go further back and create a new timeline, to Cell reprogramming it (intentionally or accidentally) works.

You've offered up an interesting solution overall (and as suggested, I don't use guidebooks when forming opinions, just wanted to supply the link to flesh out the conversation with another POV). The only leap is the existence of a permanently dormant Cell. I guess it's also possible that the Androids could have taken him out on their own. I wonder if it's possible to explain things differently without a dormant Cell, so I'm looking forward to other theories.

The main problem, is that Trunks posited that the differences (Androids 19/20 existing, the timing of Goku's heart disease, and I think both he and Kami noted that 17/18 were not only stronger than in his timeline, but at the time also suggested that they were less evil), were caused by the existence of Cell. So if just Cell had traveled back, whether or not he did anything in Trunks's timeline, that would go against that plot point (since Cell was dormant almost right up until Kami/Piccolo fused, so it wasn't him acting out that caused a timeline divergence, but the fact that he had traveled back in time) leading up to Cell's introduction.

Maybe alternatively to the butterfly effect, it actually just was a paradox of Cell and Trunks meeting. Because if they never met, then the timeline wouldn't need to split. I don't know if this makes sense mechanically though. The Trunks from Cell's timeline had to go *somewhere*, and it wasn't the main story timeline. So this would mean, the second Trunks gained knowledge of Cell existing, his timeline split, just by virtue of him knowing about Cell.

If I'm being honest, I don't think this is mendable, and there might be a fundamental issue with the writing.

[Neo-Makaiōshin]

Not sure if this will help but this discussion made me remember about that video.

[Sayo-chan]

Snip

What about the Cell in the red timeline? That Trunks wasn't aware of his existence, so it's possible they never found out about him.

[Zephyr]

What about the Cell in the red timeline? That Trunks wasn't aware of his existence, so it's possible they never found out about him.

I guess it's up to you whether or not you think that they found and killed little baby Cell when they found blueprints in the lab, or if you think he managed to mature and then showed up by the time when little baby Trunks became an adult. Everyone is alive in this timeline: Goku, Vegeta, Gohan, etc., albeit with none of the events that prompted the use of the Room of Spirit and Time, so no necessary further evolution of the Super Saiyan form (no SSj2 for instance, and thus no Buu). I mean it could still happen, but there's no real directly apparent impetus for it. Regardless, by the time he matures, I doubt he'd be much of a threat to any of the more powerful good guys. Although I guess anything could happen.

That would actually be a really interesting timeline to explore. I already have the headcanon that Movie 7 occurs within it, but it'd be awesome to see it expanded further. There really wouldn't be anything getting in the way anymore of Goku and Vegeta's rivalry (no Cell games, no dead Goku, no Majin Buu), so they could finally have their little death match, however that would end up turning out.

[dbgtFO]

I go by Zephyr's explanation too. That's what makes the most sense to me.
Fundamentally it comes down to Cell's arrival in the main timeline, because if we just follow his steps, we have:

1) The Original Timeline
Age 764: Goku kills Freeza and Cold.
At some point between Freeza's death and the wakening of the androids, Goku dies because of the heart virus.
Age 766: Trunks is born.
Age 767: Androids kill Vegeta, Piccolo etc. Only Gohan survives and there are no Dragon Balls.
Age 780: Gohan is killed by #17.
Age 784: Trunks loses to the androids and goes back in time to give Goku heart medicine in age 764, creating AT1.
Age 785: Trunks makes his 2nd trip to AT1 to help out against the androids in age 767. He then returns and defeats the androids with shut down device.
Age 788: Cell kills Trunks and goes back further in time, creating AT2.

2) Altered Timeline 1
Age 764: Trunks(OT) kills Freeza and Cold.
Age 766: Trunks is born.
Age: 767: Androids attack, but are eventually defeated by the use of the shut down device, that the Dragon Team stumble upon. Trunks(OT) returns home.

3) Altered Timeline 2
Age 763: Cell(OT) arrives from the future.
Age 764: Trunks kills Freeza and Cold.
Age 767: Androids attack, but are absorbed by Cell(OT), who holds the Cell Games, but is killed by Gohan.
Age 774: Buu Arc etc.

The question being, where does the Trunks, that killed Freeza and Cold in AT2 come from? You have to have a 4th timeline that repeats the events of the original timeline, but somehow without having a timetraveller having travelled to it for it come into existence in the first place!
It just doesn't make sense and so I go with Zephyr's explanation and it looks like this:

1) The Original Timeline
Age 764: Goku kills Freeza and Cold.
At some point between Freeza's death and the wakening of the androids, Goku dies because of the heart virus.
Age 766: Trunks is born.
Age 767: Androids kill Vegeta, Piccolo etc. Only Gohan survives and there are no Dragon Balls.
Age 780: Gohan is killed by #17.
Age 784: Trunks loses to the androids and goes back in time to give Goku heart medicine in age 764, creating AT1.
Age 785: Trunks makes his 2nd trip to AT1 to help out against the androids in age 767. He then returns and defeats the androids with shut down device.
Age 788: Cell kills Trunks and goes back further in time, creating AT2.

2) Altered Timeline 1
Age 764: Trunks(OT) kills Freeza and Cold.
Age 766: Trunks is born.
Age: 767: Androids attack, but are eventually defeated by the use of the shut down device, that the Dragon Team stumble upon. Trunks(OT) returns home.

3) Altered Timeline 2
Age 763: Cell(OT) arrives from the future.
Age 764: Goku kills Freeza and Cold.
At some point between Freeza's death and the wakening of the androids, Goku dies because of the heart virus.
Age 766: Trunks is born.
Age 767: Androids kill Vegeta, Piccolo etc. Only Gohan survives and there are no Dragon Balls.
Somehow Cell(OT) ends up dead. Let's just say, that the androids in their random rampage lucked out and destroyed the very field Cell was developing in(as Cell first reached his 1st form a little while after the initial Android attack, leaving enough time for the androids to destroy him before he could complete his development).
Age 780: Gohan is killed by #17.
Age 784: Trunks loses to the androids and goes back in time to give Goku heart medicine in age 764, creating AT 3.
Age 785: Trunks makes his 2nd trip to AT3 to help out against the androids in age 767. He then returns and kills the androids with superior power.
Age 788: Trunks kills Cell.

4) Altered Timeline 3(Main Timeline)
Since Trunks(AT2) travels to a date(764) after Cell(OT) had already arrived(763), Cell(OT)'s existence is a part of the history of AT3, thus there were 2 versions of Cell(OT) travelling back in time, one somehow got killed before getting to absorb the androids, thus barely making AT2 different from the Original Timeline and the other is the Cell we know, who held the Cell Games and got killed by Gohan.

[AvatarReiko]

@DBGTFO

He is created as result of Cell travelling back to date prior to Trunks'(the one Cell killed) original arrival in 764. From Cell's prospective(who arrived in 763), Trunks had not arrived yet to warn the Z-senshu. This created another FutureTrunks(the main one).

[Truhan]

I have a theory dealing with two worlds that already exist, whose past events branch by interference of the future. In this theory, there's no instance where Goku defeated Freeza and King Cold in the main line, because that's our assumption of what would happen had Trunks not interfered. However, Trunks' future timeline was without his own interference.

C -->> D -->> A -->> B -->> C - Trunks and Cell's perspective.

This is what happen in each:

A -->> B - Cell #1 is destroyed by Gohan and Trunks #2 travels to Future C.
B -->> C - Cell #2 kills Trunks #2, who destroyed Cell #1, and goes after Trunks #1.
C -->> D - Cell #2 is destroyed by Gohan and Trunks #1 travels to Future A.
D -->> A - Cell #1 kills Trunks #1, who destroyed Cell #2, and goes after Trunks #2.

Where #1 and #2 are different versions of the same character, depending on iteration. To sum it up, what happened is as follows:

- one Trunks departs from the future, because another Trunks prevented Cell from killing him, and then got killed by another Cell, which went after the first Trunks;
- the Trunks that departed arrives back just in time to prevent Cell from killing the Trunks that is about to depart, hence the cycle being kept.

This way, the Past can be altered without affecting the Future, as if they were two worlds interacting with each other. However, Future Trunks would be dead after Cell killed him to steal the time machine, and no contact would be made. If Xenoverse's Trunks is the same one from the Cell saga (among other things that disapprove this idea), then it woudn't be possible.

Now let's introduce the main line as it developed from B and D, which are two instances where Gohan killed Cell.

B --> B1 --> B2 --> B3 -- etc.
D --> D1 --> D2 --> D3 -- etc.

There are as many alternate worlds as the number of times we witness Future Trunks departing to them.