Terms Mystique by catt dahman

After eight books, this is the ninth and the grande finale, the final whimper of a world taken over by a zombie apocalypse. Bringing old friends, old enemies and a mass horde of zombies together for a final battle, everyone realizes that there is another player in the game: one will will destroy them all if it can.

This is the last story of the survivor's fight against the creatures and they never knew that George's terms were not quite as simple as they believed; they find that his terms held a last, devastating mystery. Nine isn't just the number of the last book: it's all who will be alive in the end.

Z is for Zombie Order:

George’s Terms

Event Horizon

Shadow of Doubt

Devil’s Details

Rage

What Lies beneath

Avenging Angel

End of the Road

Terms Mystique.