Sahih Bukhari

Narrated Abu Huraira:The Prophet (ﷺ) said, ""The most awful (meanest) name in Allah's sight."" Sufyan said more than once, ""The most awful (meanest) name in Allah's sight is (that of) a man calling himself king of kings."" Sufyan said, ""Somebody else (i.e. other than Abu Az-Zinad, a sub-narrator) says: What is meant by 'The king of kings' is 'Shahan Shah