Luke is the main character. He is 17 and is the only son of a noble family in the kingdom of Kimlasca-Lanvaldear. After a kidnapping incident, all of his childhood memories are erased, causing him to be very selfish and ignorant of the real world.
As the game progresses, Luke learns that he is actually the "replica" of Asch, the real Luke fon Fabre. This event, along with the abandonment of his friends, prompts Luke to change himself for the better.

Source:Wikipedia