At Least with Sorrow - S1.E23

Left with no choice, Lelouch shoots and mortally wounds Euphemia in front of Suzaku. Suzaku returns to the Avalon with her battered body as the Black Knights continue to contain the violence. She succumbs to her injuries as Lelouch announces his plan for the creation of the United State of Japan. Alone, Lelouch grieves over his actions as C.C. comforts him, reminding him that she will stay alongside him, as per their contract. Soon, the entirety of Area 11 revolts against the Britannian Empire. Advancing with his massive army, Lelouch ignites the conflict by initiating the collapse of the Tokyo Settlement.