Mangekyō Sharingan

The most powerful form of the Sharingan, the Mangekyou Sharingan (translated to the Kadieoscope Sharingan in some translations) seems to be a form of kekki genkai that would be pursued by all Uchiha clan members. However, almost no one pursues this powerful kekki genkai because a requirement to obtain it is to kill your best friend. Itachi himself states that only two people has obtained the Mangekyou Sharingan, and adds that Sasuke has potential to gain this form of the Sharingan too.

Known Users

 * Itachi Uchiha
 * Kakashi Hatake (he uses a different form)