Lightsworn

Lightlords (soon-to-be re-named as Lightsworns) are a set of monsters introduced in Light of Destruction. Their primary effect involves self-milling, aka sending cards from the top of your deck to your graveyard, either as a maintenance cost or as a cost to activate their effect. This may seem like a bad idea, especially since currently the Lightlords don't have any way of preventing this discard effect, but two of their most powerful monsters - Lightlord Dragon Gragonis and Judgment Dragun - require a good number of Lightlord monsters in the graveyard to activate, and another Lightlord monster - Lightlord Beast Wolf - can be Special Summoned when sent from the deck to the graveyard.