Here's what I imagine now for the Cakulha scenario in chapter 12. It's a bit long, even though I try to be concise:
The cast has returned from the "Reptite timeline". Belthasar informs the party that a Reptite called Cakulha is causing some crisis on Zenan mainland. The political situation in the future is complicated, so Belthasar feels the need to explain it to the party...but first, he tells them to recover the Epoch in 1,002 A.D. in case something would happen to Chronopolis.
After doing so and returning, the party learns about the future political situation. Another long Belthasar speech would probably be too much at this point, so what we can have is Belthasar telling the party to check the computer for the information, if they want (if not, they can go directly). So: in the aftermaths of a disastrous nuclear conflict in the 22th century, the nations of the world decided to unite in a Central Regime to prevent other tragedies. In reality, the Vanguard organization is almost synonymous with this regime: it controls most of it. Rebellions form from time to time but are always easily crushed. In 2,302 A.D., the situation is different because of Cakulha. He joined the current (terroristic) rebellion and has managed to acquire a nuclear missile that they plan to use on a city of the Central Regime. Belthasar doesn't really know why Cakulha joined them, but the party has to take care of him in any case.
The party makes its way in the rebel base fighting a few robots and a majority of human enemies (we'll replace Krawlie with a mecha-armored fighter...or something). Whenever there are no enemy around the party to hear him, Cakulha appears on a computer screen and ask the party ethical questions about what they did to his world. He also reveals that his only goal in this conflict is to gather resource and acquire the means necessary to find Chronopolis. He can't directly use the resource of the Central Regime, because he doesn't want to tell anyone about the Time Fortress and because they'd have used him as a guinea pig if they ever found him. So he joined this non-xenophobic rebellion instead and tries to make them overthrow the regime. After all questions are answered, one out of three possible outcomes for Cakulha is reached:
1. He commits suicide.
2. He's defeated in battle by the party.
3. He tries to stop the missile launch but is killed by the rebels.
In the end, the remaining rebels manage to launch the missile regardless of Cakulha's fate. The party jumps in the Epoch and blow it before it reaches its target. At the minimum, the cutscene will show the missile, the Epoch, and some rebel jets flying above the ocean, and an explosion with DrawGeometry and fire explosion sprites. If we can, we'll add lateral close-ups of the flying stuff, some sort of view of the city, etc.
After returning to Belthasar, the party is told that a few rebel robots actually managed to hear Cakulha and them mentioning Chronopolis, and that rumors of its existence is starting to spread on the mainland. Proto 5-02C might or might not be mentioned, but I don't think a side-quest with him is feasible. People don't believe those robots, except the Vanguard of the Central Regime... For now though, Belthasar allows/lets the party go visit Ayla in Prehistory. Thus the next chapter is unchanged except for the Epoch.
At the end of chapter 15, the Vanguard cease to exist to threaten Chronopolis, but Belthasar explains that the Central Regime still formed, though it's slightly less powerful and totalitarian. It doesn't try to find Chronopolis.
Overall, this chapter is quite heavy in terms of plot/background, especially with the 2 layers, Cakulha and the political conflict. This flows well with the rest of the plot though. After the relative simplicity of the Reptite world, we return to the complicated and contradictory human world in which the lone Cakulha is simply crushed by the events surrounding him...
