Geass
Geass is the supernatural power at the heart of the Code Geass franchise. Bearers receive a unique ability—often activated by eye contact—granted through a contract with an immortal Geass bestower. The most famous example is Lelouch vi Britannia’s Geass: the power to command absolute obedience, which he uses as Zero to lead the Black Knights against the Holy Britannian Empire.
Other characters possess different Geass abilities across Code Geass: Lelouch of the Rebellion, R2, and later works. The nature of Geass, its cost, and its link to C.C. and the Code drive much of the series’ plot and themes of power, free will, and sacrifice.