I promised you vampires in Russia, and here it is!
Twelve, by Jasper Kent, is set during the French invasion of Russia during 1812. Aleksei Ivanovich Danilov is a member of a very select group of Russian officers tasked with espionage and irregular warfare to hamper the French invaders. One of the other officers has invited a group of mysterious strangers of his acquaintance, to help. He met them during the late war against the Turks in Wallachia and was impressed by their abilities. Aleksei and the others are none the wiser as to the nature of these 'abilities', but gradually it dawns on them what they truly are. The elastic nature of morality, both political and personal, is stretched to breaking point and once the true horror is revealed, Aleksei must make a choice.
I really enjoyed this book a lot, even though there were some anachronisms that jarred, especially the use of 'OK' in the dialogue. Beside this, the author really set the scene well and developed a very believable main character faced with an impossible dilemma posed by conflicts of loyalty in his personal and professional life. I didn't see the twist at the end coming, although there were indicators through the story.
I have been toying around with a similar plot for about a decade now, so I was a bit worried that he'd beaten me to the punch, but luckily there's enough that's different between this story and my idea. It's spurred me on to develop my idea more, though.