Key information
In The Binding of Isaac: Repentance, players can unlock Tainted versions of original characters, which feature unique mechanics and abilities. These variants are essential for players aiming to achieve full completion of the game.
To unlock these characters, players must access a specific room near Mom's bedroom in the Home floor using the Red Key item. Alternatively, players can utilize a Cracked Key, which functions identically to the Red Key for this purpose.
A reliable method to obtain a Cracked Key involves dropping a trinket in any boss room before collecting Dad's Note. During the ascent back to Home, that trinket transforms into the required key. Players must navigate to the Mausoleum by using The Fool card after picking up The Polaroid or The Negative to teleport back to the floor start.
Upon reaching the Mausoleum boss room, players collect Dad's Note to initiate the ascent. By clearing enemies and following the light beams, players can return to the Home floor to unlock the Tainted character corresponding to their current run.
