I absolutely love these books by Trinity Faegen. She is great at telling a romance love story with an alpha-dog male as a lead role. This is the third book in the series. The Mephisto brothers are the sons of Mephistopheles who is known in German folklore as a demon or the devil. In this series their father is the gatekeeper of Hell. The only way for the Mephisto brothers to enter Heaven and be redeemed is if they find their one true love, and actually fall in love with her. Trinity is picking off Mephisto brother after brother in each book, writing about how they find their one true love (Anabo). Eryx (evil brother) is still out to make their lives miserable and take their Anabo for himself. Satan actually has a good deed moment, it was a little unnerving. I've never experienced a "go Satan" moment before. In The Mephisto Mark, Phoenix is the one to find his Anabo, and it's about time.
This series is very good. Give the first two a try, I cannot seem to find where to purchase this book exactly, I will post a link as soon as I can find one. The Mephisto Covenant (Book 1) and The Mephisto Kiss (book 2) are available for purchase through Amazon.