Altars are the currency for which you pay the costs for all cards and abilities. You may Build one Altar in each of your Kingdoms per turn. There is a maximum of any combination of five Altars and/or Temples allowed in each Kingdom you control. Altars are free and unlimited resources. You don't have to do anything to gain access to them, simply choose which Altars (of the five Gods) you want to Build in each of your Kingdoms on each of your turns.
Altar to Contagion - This Altar adds Devotion for Contagion, God of Decay
Altar to Grandeur - This Altar adds Devotion for Grandeur, God Glory.
Altar to Infestation - This Altar adds Devotion for Infestation, God of Growth.
Altar to Occult - This Altar adds Devotion for Occult, God of Mysticism.
Altar to Strife - This Altar adds Devotion for Strife, Lord of War.