Deals with the Devil can also utilize an excessive health stat. If Isaac's health surpasses 12 hearts, he will not gain any additional Heart Containers and further Heart Containers granted by most items will be Soul Hearts instead, but Guppy's Paw will be able to use those excessive health stat values to gain further soul hearts.
In original Binding of Isaac, the player can have up to 12 Heart Containers and there's no limit for Soul Hearts, though they can't be seen if there's more than 12 hearts in the 'Life' section. In Rebirth, the player can have up to 12 hearts in total, this also counts Soul Hearts. Note: The only exceptions for this rule is from Azazel and ?, who have -1 health, because Azazel has black hearts, and ? Has soul hearts. Two Health means two heart containers, and so on. The total number of hearts the player has.
