Within These Depths by Katze Snow

Tanner is so close to his revenge that he can almost taste it. With an unusual brand of negotiation skills under his belt, he has everything he needs. Now all that stands between him and destroying Elijah Ravenhill is a dangerous mission into the depths of Hell. Accompanied by his guides, he will enter where loyalties and souls are tested, and few everreturn.
Newly mated Alex just wants to keep his loved ones safe. In the sprawling grandeur of Wulfric Manor, he finally has his family under one roof, even if it may only be temporary, and his dreams of having something normal seem to be within reach. Yet what’s normal for the wolf is torture for the prey, and chaos descends on Alex with one mysterious phone call.
Can Alex have all he ever dreamed of without sacrificing his life? Will Tanner put an end to Elijah once and for all, or will his revenge go up in smoke within the fires of hell itself?