Council of Thirteen

At the beginning of your upkeep, draw cards
equal to the number of unique names among
Skaven creatures you control.
If you control 13 permanents, you may cast
Council of Thirteen without paying its mana cost.
The council actually consists only of 12 members, titled the Lords of Decay, the Horned Rat being figuratively the 13th member. It gathers in Skavenblight and attempts to lead all Skavendom, a most difficult task.