Whenever Rakdos the Defiler attacks, sacrifice half the non-Demon permanents you control, rounded up.
Whenever Rakdos deals combat damage to a player, that player sacrifices half the non-Demon permanents they control, rounded up.
5/1/2006 To calculate the number of permanents that must be sacrificed, count the number of permanents the affected player controls that don’t have the subtype Demon, then divide that number in half and round up. For example, a player who controls eleven non-Demon permanents will need to sacrifice six of them.
5/1/2006 A permanent with the subtype Demon, including Rakdos the Defiler itself, can’t be sacrificed this way.