The Game of Leaf and Smile — Lawrence M. Schoen

Kjest is a young demon, a Pain Lord whose only talent is winning tourneys and taking his opponents power as his own. A demonic lottery forces Zhole, eldest of the Lords of Disease, from the peace and quiet of his retirement to answer the upstart's challenge. On a Halloween night in a Philadelphia suburb, they will play a game with humans as tokens. Now Zhole, the demon responsible for the plagues that killed half of Europe, must elicit moments of delight and instants of joy from the game pieces, while Kjest strives to have them touch or be touched by leaves, again and again. The demon with the higher count wins not just the other's power, but the souls of the game pieces as well.