Once the party finally completes the ritual and the Protagonist fully awakens as the fafnir, Bertrand reveals himself as being the previous fafnir, who didn't complete his task and was left to roam the world for a hundred of years. Seeking to atone himself, Bertrand chooses to absorb the power of the fafnir to himself, becoming the next guardian in the protagonist's place. However, as he was not the chosen one by Arianna, this would result in him losing all of his humanity, while not achieving the power of the fafnir. Thus the party is forced to battle his semi-complete transformation, before they lost their trusted companion and friend.