Corruption

In a universe vastly different and very much advanced from ours, humanity is on the face of extinction due to a long lasting war with the demons of Azarath. A black mist the demons spread are said to infect and kill anyone that inhales it and it only takes a couple of minutes for the effects to kick in. Those who have been lost to the mist are resurrected themselves as demons, humans have dubbed them the "Corrupted". Humans who are prepared and skilled in combat are sent out to take back landmarks humanity once had. 

Goal of the game (which will be broken into episodes) is to figure out a way to stop the corruption and war.