Code Geass: Lelouch of the Rebellion

In 2010, the Holy Britannian Empire conquers Japan and strips its people of their name, rebranding the country as Area 11 and its citizens as "Elevens." Seven years later, Lelouch Lamperouge, a brilliant, bored student at a Britannian school, is secretly an exiled prince with a deep grudge against the empire and its ruling family. When a chance encounter pulls him into a military conflict, a mysterious girl named C.C. gives him the Geass, a power that lets him force anyone to obey any command, though only once per person. With it, he becomes Zero, a masked revolutionary who takes up the cause of the Japanese resistance and leads the rebel group known as the Black Knights, using the Geass and sharp strategy to outmaneuver the empire's giant Knightmare Frame mechs. His goal is to destroy Britannia and build a kinder world for his younger sister, Nunnally, but his path collides with Suzaku Kururugi, his childhood friend, who is now fighting for the empire on the opposite side. It's a gripping mecha thriller driven by chess-like schemes, bold twists, and a hero who is willing to pay any price for his ideals.