Till Death by Harper A. Brooks

Part reaper. Part angel. All trouble.
With God still out of the picture, the war between Heaven and Hell rages on. The living and dead have joined together to stop the apocalypse. Yet, in the midst of the carnage, Jade Blackwell has left the battle to embark on a mission of her own. To save Cole Masters from the pits of Hell.
After sacrificing himself to protect her, Cole’s tortured soul is trapped and inching ever closer to becoming a Halfling minion. Getting him out will mean breaking every rule in Heaven’s handbook and venturing into the depths of Hell… again.
Demons.
Halflings.
Deadly traps.
Around every bend a new threat awaits.
With the war being fought top-side, the world needs Jade to assume her place as their leader now more than ever. But despite all the risks, she’s determined to keep the promise she made to Cole—that she would find a way to free him of his demon. No matter what.
If she loses sight of him now, he’ll be lost to her forever.