Wicked Obsession, so I thought I'd take a moment to give some details related to that character which might help explain what a mal vampire is exactly.
In Wicked Obsession, during Julian's youth, he was in a house fire, and his body was left scarred. Because the damage was caused by fire, he could only heal from it to a degree. Vampires in my universe are creatures who pride themselves on their strength, good looks, and immortality - which is tied to their ability to heal. They consider scars of this nature to be a terrible flaw, and often, something to be ashamed of.
Before Eleni's arrival at his chateau, Julian had remained closed off from the world because, in his opinion, he is flawed due to his extensive scars. It is his love for Eleni that brings him out of his shell and allows his heart to heal.
Where did the term mal vampire come from? I made up the term to describe vampires who had suffered some kind of misfortune that made them "less desirable" in the eyes of vampire society.
On its own, the word mal in French, means "poorly", "bad", "wrong", but is typically used to describe a verb. Mauvais vampire would be the term I'd use if I was simply trying to convey that Julian is a "bad vampire". But that wasn't my intention. The term mal (the way I'm using it) was loosely inspired by the Malheur (misfortune) card in the Oracle De La Triade. (Edited to add: a similar card would be "misfortune" in the Leonormand Gypsy deck.)
In my novels, vampires who have suffered physical traumas, whether by fire or other means, are mal(heur) "misfortune" vampires. However, because they are a globalized society of vampires, with Russians living in America, and Americans living in France, I felt that over time, the vampires probably would've simply shortened malheur to mal and embraced the shortened phrase mal vampire as a sort of double entendre. I hope this helps explain the origins of the mal vampire.
The first book in the series, Wicked Temption, is still out of print. Thanks for your patience.
Wicked Obsession is available online at Smashwords, and is available in print on Amazon.