I think you're striking on some great points of inspiration and I can't help but be interested in this unique blend of historical fantasy and gothic indulgence. I have a possible idea brewing...a man from British-colonized Botswana, instructed by Lutheran missionaries in subjects such as Dutch and devil hunting, who initially helped the diamond magnate Cecil Rhodes when the mines of his newly-established De Beers Group disturbed ancient evils hidden beneath the earth. After being recognized there for his skills he could end up bound on a ship to Europe in order to help quell the growing scourge up north.