Arglas

Arglas is a character in Xenoblade Chronicles. He is a member of a race of beings known as Giants. He is never directly met during the events of the game since his body is possessed by Zanza when Shulk and his friends met him on Prison Island. However Arglas is seen in flashbacks.

Before Xenoblade Chronicles
Long before the events of the first Xenoblade, Egil and Arglas were good friends who wished for the continued peaceful lifestyle that the inhabitants of the Titans, the Bionis and Mechonis, were enjoying. Arglas wondered whether any of the inhabitants of their worlds would ever try to leave, and seek out new life on whole new worlds beyond the endless sea that surrounded the Titans. Egil admited that he had never considered it before.

The Monado's Influence
Unfortunately, Arglas was drawn to the Monado's power and came across it. Zanza took possession of his body and, through using him to antagonise Lady Meyneth, and thus the battle between Mechonis and Bionis began.

Eventually the battle came to a cease, as both Gods became too weak to continue. They both went into rest, waiting to regain enough strength to continue the battle. This is what led to the inhabitants of Bionis believing the Bionis was dead. In a weakened state, Zanza (still in Arglas body) allowed himself to be captured by the High Entia race who tried to prevent their own doom. Sealed away in Prison Island inside the body of Arglas, Zanza began to rest, recovering his strength and waiting for the birth of the true heir to the Monado.

The True Heir
Shulk arrives at Prison Island and meets Zanza, still inside Arglas' body. Shortly after being released from his prison, Zanza is stabbed by Metal Face's spear. This kills Arglas' body and leaves Zanza as a spirit. At this point in the story, Arglas officially dies.

Trivia

 * Arglas's name is similar to that of Atlas, a Titan in the Greek mythology.