Iron Will is gold Tarot Card obtainable in Ruins and in Studios. When it is equipped the player becomes invulnerable and cannot be hurt by monster's attacks. It costs 666 gold. To acquire it, player has to kill Guardian in less than 1:20 (in Ruins) or keep Health Points above 50 (in Studios).
In Painkiller Hell & Damnation this card can be obtained in Orphanage and costs 666 gold. To acquire it, player has to gib 50 frozen monsters.