Nasir, or Nassel in the Japanese version, is the Champion of Light, and also known as the Child of Light, who was brought to Earth with the Child of Darkness, Thor. Nasir is the main character in the game that will investigate the dirty water, defeat demons, save people and more.

In the intro in the beginning when you start a new game Mathias says this to him:

NASIR, I have raised you to be the Champion of the Light... Now it is time for you to fulfill your destiny. Listen carefully. The water around Lakeland has recently become muddy. It must be a sign of something evil. The muddy water must have something to do with the demons that are appearing everywhere. I want you to find out the cause and bring pure water back to this land. First, you should go to Atland which you know well.