Why is Sudan in crisis?

Sudan is in a religious civil war. Half of the country are Muslim and half are christian. They've been in a brutle war with one another for quite some time. No one in the world is doing much to stop this crisis. thousands of people are dying daily and the world is doing nothing to help. I think with small help from the top countries in the world this manslaughter could easily be stopped and hundreds of thousands of lives just may be saved.