Answer
Riina's other nickname was "Il capo di tutti capi", which means "the boss of all bosses" in Italian. This nickname was given to him because of his high-ranking position in the Sicilian Mafia. He was the leader of the Corleonesi clan, which was one of the most powerful clans in the Mafia. Riina was responsible for many murders and other crimes, and he was eventually sentenced to life in prison.