Aeon Pneuma - Spirian Saga Book 4 by Rowena Portch

No pain compares to the loss of your soul. At least that’s what Elle believes until she meets Avel, the Spirit of a man who died over 300 years ago. Avel doesn't know why he, of all Angels, has been sent to deal with a rogue necromancer, but here he is, sent to recover a book that Vincent intends to use with evil intent. Elle, the female who has the book, does not know the danger she's in. Her true identity complicates matters further and draws Avel into a spiral that links his unbearable past to the present. Will they survive, or succumb to the pain of an old wound that never truly healed?