Parasite by Soren Summers

It’s been one hundred and forty-five days since the world ended. Paragon has swept through the city of Pleasance like a reaper’s scythe. Now the dead walk the earth, seeking the flesh of the living. Still Jarod Samuels refuses to die.
As a hunter, Jarod safeguards the Hive, the ruined mall he calls home. He exterminates zombies to protect the city’s last few survivors, and to keep Gabriel Anderson unharmed, their lives intertwined now more than ever.

But in a city ravaged by Vertex’s corruption, there’s no telling what dangers each day will bring, whether the threats within the Hive’s walls might be deadlier than those without – or whether monsters from the past still lurk and linger in the city’s shadows.​