Necromancer is a transformation in The Binding of Isaac, added in the Repentance+ DLC.

Obtained by acquiring the following 3 items and trinkets: The Necronomicon, A Missing Page, and Missing Page 2.

Changes The Necronomicon's display sprite and gives it a special purple charge bar that can be used 10 times per floor.

After the 10th use, The Necronomicon gets back its old sprite and the charge bar is reverted to the usual 4-pip bar, but fully depleted.

The purple bar is restored when traveling to the next floor.

The Necronomicon cannot be recharged normally while the purple bar is active.

• Check out the transformation description on the external Isaac Wiki.