A Dreary Midnighter
SPOILERS AHEAD! BE WARNED!
He buys skeletons to export to the Surface for some mysterious purposes.
Game Instructions: He's only interested in realistic skeletons – that means no chimeras, no amalgamy, no false-saints, and absolutely no oversized bats. He will pay you in Fistfuls of Surface Currency and a Vienna Opening.
Unlocked with redirect from Sell to a Dreary Midnighter