Empty Vessel

Empty Vessel is an unlockable passive item added in Afterbirth.

Effects

 * Grants 2 Black Hearts on pickup.
 * When Isaac has no red hearts:
 * Grants flight.
 * Every 40 seconds, when in a room with enemies, a shield triggers, nullifying all types of damage for 10 seconds.

Synergies

 * The Lost, ???: Since these characters can never gain red hearts, Empty Vessel will always be activated.