An Assassin and an Artist

Marin Deschamps has led an interesting life for the past one thousand years. Born a shifter, and also a healer with magical abilities, he still would have died in battle if vampire Baptiste hadn't turned him. Although his Sire didn't approve, he became an assassin, working for nobles who needed his services. As the centuries passed, he plied his trade or fought in various wars until, in the late eighteen hundreds, he settled in Denver, where he used his impressive skills to protect those who needed them.
Never once in all that time has he allowed anyone into his life -- until now. Tyler Campbell is an artist and a nascent author who is writing a book on the early history of Denver. While sketching the tunnels below the city to illustrate his book, he meets Marin, who is there for reasons of his own. Tyler is instantly drawn to the handsome, amber-eyed man. A man he has no reason to believe is anything other than another human, although humans are aware that supernaturals live among them.
Marin is appalled when his panther reveals that Tyler is his fated mate. Things get worse, in his opinion, when he needs Tyler's help to stop a vicious gang of humans bent on destroying all supernaturals. Will they be able to stop the gang, and if so, will Marin's vampire half allow his growing interest in Tyler to become more? If he does, he will have to reveal what he is, which could destroy any hope that they might have a future together.