|Hellen is the devil's own. Literally. Her father, Abaddon, is the king of Hell, and has sold her to the highest bidder — an evil vampire, Cruen, (who knew there was such a designation between vampires or demons?) whose duty it is to breed a demon that can live in both Hell and the earthly plain.
Enter Erion, one of Cruen's misbegotten sons. To draw Erion back into the fold, Cruen has recently made off with Ladd, Erion's only son from his first and only sexual misadventure. In retaliation, Erion takes an eye for an eye by kidnapping Cruen's blushing succubus bride and holding her prisoner with the intent of trading her for Ladd.
When the time comes to make the trade, Erion, despite his raging attraction for the demoness, hands her right ove r — only to discover that his father has already taken the child to the Underworld. We proceed to the Underworld, where things go on rag-tag as they have for the first half of the book, though Erion and Hellen are each slowly coming to realize that the other is acting a tough part for their own protection (also, they both seem to honestly be inept jerks). They—finally—decide that together they can take on Cruen and Abaddon if it means saving those few that they love.
Well, if you've been waiting with baited breath for vampire cavemen, Eternal Demon by Laura Wright is your book. The three-heart rating is an average; Eternal Demon started off as a four-star book and went downhill from the third chapter. It bottomed out at two without guttering entirely. The characters are shallow and sometimes downright unlikeable, the plotlines are too crowded, and the dialogue is stilted. But, there are some funny times and the few sex scenes are hot, so it's up to you to prioritize.