I don't understand why Home World is doomed thanks to Serge

[Beach Bum]

According to the theory on the Compendium, it's because the timeline was split and Crono's group can only exist in Another World. Why is that though? Home World's history pre-1010 AD should be just a carbon copy of Another World. And so it should have its own Crono who departed in 1000 AD on a journey through time to stop Lavos. There's no reason for there to be differences in Home World's history pre-1010 AD if the timeline was split in 1010 AD.

Even if that would be the case though, there being no Crono to save the world from Lavos in Home World is no fault of Serge. It was Kid and Belthasar ultimately who are responsible for the dimensional split. Yet Crono, Marle and Lucca in the Dead Sea seem to blame Serge very personally. Lynx also refers to Serge as the "assassin of time". Why? If anything, they should all be pissed at Belthasar.

[Razig]

My personal theory is that Serge's existence threatens the world because he threatens FATE. Without him, FATE keeps the Frozen Flame and the Dragons locked up and everything is good (at least until the Time Devourer matures). But with him in the mix, FATE loses control and the Dragons use the Flame to revive Lavos, which is now unstoppable due to all the power it has amassed.

That's just my theory. It's got some holes in it: it kind of presumes that Serge is destined to defeat FATE but not the Dragon God, and the Chrono series is against predestination. But it's the simplest solution that makes sense to me.

[Boo the Gentleman Caller]

Ah, the whole Serge as the Assassin of Time argument. Definitely a mystery to be sure.

In a nutshell, I'd like to think that it's all about Serge and his role as the Arbiter with the Frozen Flame. Had he failed, he would have somehow merged with the Time Devourer, allowing the post-Lavos Time Devourer direct access to the Frozen Flame once more. This would ultimately allow the Time Devourer to mature and destroy all of space-time.

I believe the Dead Sea is a piece of that destroyed future. Despite looking like it's from the "bad future" 2300AD of Chrono Trigger, it's not actually it... Dates found in the Dead Sea indicate it is indeed from 2400AD, so it has to be a negative future post-Chrono Trigger and post-destruction of Lavos.

Here's a screenie that indicates the Dead Sea future is in fact from 2400AD or later:
https://www.chronocompendium.com/Term/File:Company_2400.png.html

Now, that's all good and all, but here's some food for thought. The theory is from way back in the day, called the Armageddon Branch Theory and authored by the great GrayLensman:

Inquiry:

In the Dead Sea, the future that Crono averted has been brought back into existence by Serge's life somehow. The next inquiry involves how the destruction of the future is ensured; it is a fact that temporal change cannot be brought about in the Chrono series by possibility alone. This observation negates several theories that attempt to explain the future's destructions, most stating that Serge accidentally and indirectly causes something to go wrong when Crono challenges Lavos. This proves a compelling mystery that's explained by the nature of the dimensions.

Armageddon-Branch Theory

Crono could not have defeated Lavos in Home World. The event which spares Serge's life also creates a plurality of dimensions from 1010 onwards. Since there is only one Crono in 1000 AD to defeat Lavos, only the future in Another World is saved.

Further Explanation

In the original timeline (Another World) Serge dies in 1010 AD, but Kid changes the past, somehow creating an alternate dimension in which Serge lives (Home World). Another World always existed; it is the original dimension, but Home World only extends from 1010 AD onwards. In 1000 AD, Crono exists in Another World. If he travels through time, he can only reach a destination within his own dimension. When Crono defeats Lavos in 1999 AD, or any other time, the battle takes place in Another World. In 1000 AD, there is only one version of Crono. If Crono lived past 1010 AD, there would be a version for each dimension, but that version did not travel through time to defeat Lavos. In Home World, no savior appears in 1999 AD to save the future. Serge caused the destruction of the world by spawning an alternate dimension which is beyond 1000 AD Crono's notice or reach. He does not undo any of Crono's actions. In Another World, the future is secure, at least until the Time Devourer arrives. There cannot be multiple Crono groups because there is only one dimension in 1000 AD!

[Beach Bum]

Ah, the whole Serge as the Assassin of Time argument. Definitely a mystery to be sure.

In a nutshell, I'd like to think that it's all about Serge and his role as the Arbiter with the Frozen Flame. Had he failed, he would have somehow merged with the Time Devourer, allowing the post-Lavos Time Devourer direct access to the Frozen Flame once more. This would ultimately allow the Time Devourer to mature and destroy all of space-time.

I believe the Dead Sea is a piece of that destroyed future. Despite looking like it's from the "bad future" 2300AD of Chrono Trigger, it's not actually it... Dates found in the Dead Sea indicate it is indeed from 2400AD, so it has to be a negative future post-Chrono Trigger and post-destruction of Lavos.

Here's a screenie that indicates the Dead Sea future is in fact from 2400AD or later:
https://www.chronocompendium.com/Term/File:Company_2400.png.html

Now, that's all good and all, but here's some food for thought. The theory is from way back in the day, called the Armageddon Branch Theory and authored by the great GrayLensman:

Inquiry:

In the Dead Sea, the future that Crono averted has been brought back into existence by Serge's life somehow. The next inquiry involves how the destruction of the future is ensured; it is a fact that temporal change cannot be brought about in the Chrono series by possibility alone. This observation negates several theories that attempt to explain the future's destructions, most stating that Serge accidentally and indirectly causes something to go wrong when Crono challenges Lavos. This proves a compelling mystery that's explained by the nature of the dimensions.

Armageddon-Branch Theory

Crono could not have defeated Lavos in Home World. The event which spares Serge's life also creates a plurality of dimensions from 1010 onwards. Since there is only one Crono in 1000 AD to defeat Lavos, only the future in Another World is saved.

Further Explanation

In the original timeline (Another World) Serge dies in 1010 AD, but Kid changes the past, somehow creating an alternate dimension in which Serge lives (Home World). Another World always existed; it is the original dimension, but Home World only extends from 1010 AD onwards. In 1000 AD, Crono exists in Another World. If he travels through time, he can only reach a destination within his own dimension. When Crono defeats Lavos in 1999 AD, or any other time, the battle takes place in Another World. In 1000 AD, there is only one version of Crono. If Crono lived past 1010 AD, there would be a version for each dimension, but that version did not travel through time to defeat Lavos. In Home World, no savior appears in 1999 AD to save the future. Serge caused the destruction of the world by spawning an alternate dimension which is beyond 1000 AD Crono's notice or reach. He does not undo any of Crono's actions. In Another World, the future is secure, at least until the Time Devourer arrives. There cannot be multiple Crono groups because there is only one dimension in 1000 AD!

I've read this, but I just don't understand why there would not be a Crono & crew in Home World to save the world from Lavos. And even if there isn't a Crono & crew in Home World, that is not because of Serge's existence, but because of the dimensional split that was caused by Kid and Belthasar. Yet the ghosts in the Dead Sea blame Serge specifically, as if his mere existence is what doomed Home World.

[Acacia Sgt]

I believe the Dead Sea is a piece of that destroyed future. Despite looking like it's from the "bad future" 2300AD of Chrono Trigger, it's not actually it... Dates found in the Dead Sea indicate it is indeed from 2400AD, so it has to be a negative future post-Chrono Trigger and post-destruction of Lavos.

Here's a screenie that indicates the Dead Sea future is in fact from 2400AD or later:
https://www.chronocompendium.com/Term/File:Company_2400.png.html

Isn't it more like a merge of both? The 2300 AD before Lavos's defeat and the 2400 (?) AD after Lavos's defeat, when the Time Crash happened? There's stuff like the video showing what seems to be the Day of Lavos, and Johnny's "corpse" (unless, like Robo, he was built pre-1999 and thus can exist in any future post-DoL), to indicate there's at least some essence of CT's bad future thrown in there. As for 2400... isn't that just due to Company 2400? Do we even know that's meant to be a year date?

[Boo the Gentleman Caller]

Isn't it more like a merge of both? The 2300 AD before Lavos's defeat and the 2400 (?) AD after Lavos's defeat, when the Time Crash happened? There's stuff like the video showing what seems to be the Day of Lavos, and Johnny's "corpse" (unless, like Robo, he was built pre-1999 and thus can exist in any future post-DoL), to indicate there's at least some essence of CT's bad future thrown in there. As for 2400... isn't that just due to Company 2400? Do we even know that's meant to be a year date?

Great point. I guess you're right, it would be a combination of discarded timeline futures. It also references Radical Dreamers are yet another reality, so yeah, great point.

[Kodokami]

The Dead Sea should be "linked" in time with Chronopolis, if we follow the whole time bubble thing. So the Dead Sea is experiencing the same time dilation that Chronopolis is in Another World. 12,000+ years in the future, right? Lavos (or the Time Devourer) would surely have destroyed the future by then if she still lives.

As for why Lavos would still be alive in Home World, I don't know. As Beach Bum has noted, Home World's past should be identical to Another World's with its own time traveling Crono and co. Unless the Armageddon-Branch Theory is supposing a literal fork between dimensions, which I think kinda flies away from all other theories of time travel in the series.

The only reason I can see for Home World's future being destroyed is if Serge somehow merges with the Time Devourer or fails to stop her. Which brings us back to why this would happen.

[Lain]

Thing is, if the arbiter of the flame is back, doesn't that interfere with FATE's usage of the frozen flame again?
What I speculate is that locking FATE out of that essentially leads to some interference happening outside of El Nido Archipelago.
FATE's task was to ensure that nothing in the timeline was altered, yet now it can't access its main source of agency in reality, the flame, anymore.
This means that Crono could save everyone because FATE was in the background manipulating events more than anything, which really does make sense since some regular guy being that awesome sounds pretty stretched.
Serge, the arbiter of the flame, locks FATE out of using the device that allows for this kind of causality protection, therefore Crono fails to save the world from Lavos.
My question is why the concept of an arbiter of the flame even exists.
That suggests that Belthasar had all of this in mind when he created Chronopolis even, after he landed in a safe future as a result of Crono's actions. Then this stabilizes itself as he would have done all of this shit to ensure that Crono's actions would have come to pass, via them having always been protected.

[claaaus]

My question is why the concept of an arbiter of the flame even exists.
That suggests that Belthasar had all of this in mind when he created Chronopolis even, after he landed in a safe future as a result of Crono's actions. Then this stabilizes itself as he would have done all of this shit to ensure that Crono's actions would have come to pass, via them having always been protected.

The arbiter exists for protection, because FATE was using the power of lavos (frozen flame), and then it could be corrupted, I think.