The River of Hatred by Liana Valerian

A fallen angel with a grudge. A warrior of Heaven with too much to lose. And a Nephilim caught between them.

Once, Sariel would have done anything for Ithuriel. Now? He just wants to watch him fall. When the angels embark on a mission to close the rift between Hell and the human world, Sariel sees his chance for vengeance. Ithuriel let him suffer alone for centuries – now he’ll make sure the righteous angel knows exactly what it means to fall. And if he has to use their captivating Nephilim companion, Jessica, to do it? Even better.
As they descend into the twisted depths of the Malebolge, facing the damned and the demons who rule them, Sariel’s game of seduction takes a dangerous turn. Temptation was supposed to be his weapon. He never expected it to feel like salvation. And when the mission takes them beyond the Underworld, into a world where Heaven and Hell both have stakes, the three will have to decide what’s more dangerous – the ever-growing demonic conspiracy or their forbidden desires.