Darth Bane, Sith Reformer

Intimidate
Sith creatures you control have "Whenever this creature deals combat damage to a player it deals an additional X damage, where X is equal to the number of Sith creature cards on the battlefield."
Whenever Darth Bane, Sith Reformer dies, search your library for a Sith creature card, reveal it and put it into your hand. Shuffle your library.