The Mangekyo Sharingan is the evolved form of the Sharingan and one of the strongest known Kekkei Genkai in the entire Naruto series. First known to be wielded among the Uchiha by none other than Madara Uchiha and his brother, Izuna Uchiha, the Mangekyo Sharingan awakens when an Uchiha experiences severe trauma caused by the loss of a loved one.