Stargate

A great, star-spanning civilization is being gradually invaded and its member worlds corrupted by an evil entity/force which is impossible to withstand; the only solution is to isolate each infected world. As worlds fall, the survivors desperately search for an answer to the spreading chaos, and the various solutions are both heartbreaking and poignant. The main characters are not mortals; they are starfolk, bound into symbiotic relationships with the stars around which their planetary systems orbit. As such, they are almost unbelievably powerful, but against the Unmaker, even they may not be enough.