His death was the cause for the end of the world. He cares not.
He is the only one who can save the world. He cares not.
His duty demands, that he saves the world so he is doing it.

As the 57th worldmage, Rild was guarding the world nearly as long as he can remember, but the world wanted to see him dead. After he was killed, the world stood on the verge of destruction.
Resurrected to save the world, Rild has nothing from his old life. His magic is gone, his artifacts are beyond his reach, his destination is in the heart of the enemy territory. The only thing that remains is his extensive knowledge and a desire to fulfill his duty.
But why does he have to travel with the people that killed him?