From the back of the box/website:
The Order forces have put up a valiant fight against the relentless spread of the Skaven, but now a new threat has arisen, a threat that goes by name of Deathmaster Sniktch...
The Deathmaster’s Dance is the fourth monthly Battle Pack installment of The Corruption Cycle, the first linked expansion series for Warhammer: Invasion, a card game of intense warfare, clever kingdom management, and epic questing. This 40 card pack contains 20 different never-before-seen cards designed to augment existing decks and add variety to the Warhammer: Invasion metagame.
CONTAINS CARDS 61-80 of the Corruption Cycle