Grieved at the death of Serah, Noel had lost his previous personality and somehow gained the Heart of Etro by killing Caius in the past. Noel then transformed into a dark version of himself. After so many years of protecting Yeul in hopes of stopping her from dying, Noel forgets his own name. He then adopts the name of Caius. After long, his final resolve is to kill Etro, and thus, FFXIII-2 was put into action.
Sound like something Toriyama would write?
"Always forgive your enemies; nothing annoys them so much." - Oscar Wilde Currently playing: Dishonored (PC), Darksiders 2 (PS3)