Afterblight Chronicles

The Afterblight Chronicles is a series of books in a shared post-apocalyptic universe where a deadly virus has wiped out most of the worlds population (an event known as The Cull). The only survivors are those with type o-negative blood and these pockets of survivors try to eke out an existence against a decayed society and roaming bands of marauders. It's a world where only the strongest survive and many of those prey on the weak.

There are a number of novels and short stories in the series, written by authors including Simon Spurrier, Rebecca Levene, Jasper Bark, Scott K Andrews, Paul Kane and Al Ewing. Both Scott K Andrews and Paul Kane have written trilogies within the Afterblight Chronicles which have been collected in the Omnibus's School's Out Forever and Hooded Man.