The Outcasts

There's three kinds of people in this world. There's the Fliers: fortunate folk living in air homes and flying in air cars. There's the Climbers: people not as lucky as the Fliers, but still fortunate enough to be living in the trees, off the ground. But, a whole different people live on the ground. These people are the Afflicted: vicious, unfortunate, disease-ridden folks with a taste for the blood of those that are still healthy. The Afflicted are the ones who drove the Fliers and Climbers away in the first place. However, some were left behind on the ground, some that are immune to the Afflicted's disease. They don't belong anywhere in the world. The Fliers and Climbers won't bother to save them, for fear of being killed or infected, and the Afflicted want nothing to do with them but their blood. So who are they?