Battlefields.(Idea is orginally pol's)
Battlefields start out of the deck in the field of battle.
They have two special abilities. One ongoing, one instant.
Example(My own idea): Battlefield of the Soul.
Instant:You may exchange one card in hand for a demon from deck.
Ongoing:Demons Cannot be ignored.
Battlefield Specific cards.(My own idea)
These cards start inside the battlefield. You may play them at anytime you have insh.
Example for Battlefield of the Soul:
SA:Place on opponet's hero in territory. It becomes an evil character in your territory with the Special Ability "Band to a demon"