(Thresh Symbol) Presence X
You can not use costs or rules text unless you have the required Presence amongst all of the cards in play that you control.
Presence is the number of numeric thresh symbols you have in play under your control. This is ONLY for the numeric COST in the upper left of the card.
Dwarvish Grimlkin provides Presence of One Greed.
Gideon provides Presence of Three Rage.
A card would use presence as a cost requirement for cards or abilities or rules text. Example:
[R] Presence 12
This Character gain 5 strength
if it's too much to keep track of for rules text or abilities then it could just be used for cost of playing cards. (because it could be annoying to constantly recount presence to see if rules text is active or not. Then again, it just requires more skill to keep track of, lol)
One of the key things of Presence is that the abilities to meet presence require a certain amount of non-resource board position as opposed to just resource count. It also puts an emphasis on mono color.