McGann, O. (2007). Ancient Appetites. London, Random House.

Set in an alternative nineteenth century Dublin, McGann has conjured the Wildenstern family, a race mutants who are resistant to most poisons, heal from most injuries, and are enhanced by physical contact with gold.
The family is huge: over thirty members live on the Wildernstern estate itself. Others are spread across Ireland and th rest of the world. Operating trading monopolies for the British Government the Wildernsterns have grown immensely powerful and scarily arrogant. The only thing worse perhaps that being an enemy of the Wildernsterns is being a family member, because the Wilderbsterns are intensely competitive, agressive and hierarchical, and the only way to advance is through the The Rules of Engagement which permits members of the family to assassinate those above them in line.
When Nate's eldest brother dies he is forced to engage in a situation he was trying to ignore, complicated when four bog bodies are found, ancient members of his own family who slowly, very slowly come back to life and bring with them a cruder time.

I can't say much more about this book without wrecking it, and although I have no real problem with spoilers, there are some contextual twists and background elements which I'd rather leave you, the reader, to stumble over. This is too good a book for me to undermine it for you.