[via shiroha][Major Spoiler Alert] Some Additional Notes on Yesterday's Spoilers about TB and Castorice
The moment TB entered Amphoreus, they were aleady slain by Nikador, but survived due to the momentary glimpse of Fuli, the Aeon of Remembrance.
Fuli, the Aeon of Remembrance's manipulation of TB's physical form shattered the cyclical mechanism/loop of Amphoreus.
Castorice, the elder twin sister fated to battle her sibling to the death, chose self-annihilation. Her younger sister, having ascended as the Titan of Death, resurrected her elder sibling, thereby transforming herself into the Death dragon.
