In Dragon Quest XI your character is the luminary, a reincarnated hero destined to protect the life-giving tree, Yggdrasil, from the upcoming evil threat. The game begins with your character being born with a mysterious symbol on his hand that confirms his identity and marks him as a target to the forces of evil. When his hometown is destroyed by hordes of monsters, he escapes Moses-style by being placed in a floating bassinet and sent downriver. He is raised by some kind villagers and they inform him of his destiny after completing the coming of age ritual of climbing Tors summit.
Source: N4G PC Dragon Quest XI: Echoes of an Elusive Age review – ChristCenteredGamer