Caius dies, Chaos doesn't immediately infect the timeline even though Etro probably died at the exact same moment, or moments after. It waits until AFTER Serah dies to spread out into Gran Pulse. Now why could that be?
Short answer. Etro probably reinforced the gate to keep it firm and keep chaos at bay in case something should happen to her. But when Serah died, the gate had to open a little bit for her SOUL to enter into Valhalla. When the gate opened a small crack to allow that, the Chaos burst through.
It still would've happened eventually when someone else died, but she was the first to die after Caius, and thus, the chaos was released.
Notice how when,
Caius dies, Chaos doesn't immediately infect the timeline even though Etro probably died at the exact same moment, or moments after. It waits until AFTER Serah dies to spread out into Gran Pulse. Now why could that be?
Short answer. Etro probably reinforced the gate to keep it firm and keep chaos at bay in case something should happen to her. But when Serah died, the gate had to open a little bit for her SOUL to enter into Valhalla. When the gate opened a small crack to allow that, the Chaos burst through.
It still would've happened eventually when someone else died, but she was the first to die after Caius, and thus, the chaos was released.