In Assassin's Creed II, Ezio Auditore's uncle and Monteriggioni leader is Mario Auditore.
Mario is introduced as the head of the Auditore family branch based at Villa Auditore in Monteriggioni. He is also an experienced Assassin who helps Ezio after the destruction of Ezio's immediate family. Mario brings Ezio to the villa and begins teaching him about the Brotherhood and its enemies.
The Monteriggioni villa becomes a strategic home base. Ezio can restore its buildings and services, increasing the settlement's income and changing its appearance. Mario remains involved in the conflict against the Templars and provides historical and practical guidance to his nephew.
Mario is sometimes confused with Giovanni Auditore, Ezio's father. Giovanni is the Florentine banker whose execution drives Ezio's transformation, while Mario is the uncle who survives and trains him. Mario's role also continues into later parts of Ezio's trilogy.