The Last Blazemanus

A woman hides in the woods by the outskirts of a small city, creating light and sending it to the sun. People don't understand her power and fear her race - not knowing that they are what allows them to survive. One day she is caught and publically executed - people celebrate the end of the Blazemanus race. Only her child survives in the slums, nobody knowing the power they possess. The world descends into darkness and chaos as the sun begins to go out. The child grows up in this hellscape and finds some old ruins, learning about their power. They then set out to teach the world that their race isn't to be feared, they want only to help.