Suzaku Kururugi

Kururugi Suzaku is the seventh knight of the circle, a privileged Briton, the eleventh, a traitor to Japan, a numbered soldier, the knight of the third princess Euphemia, and a host of other nicknames. He was the son of Japan's last minister, whom he killed as a child, believing it would stop the war. No one knew of his actions, but his conscience torments him to this day. And the only way to atone for his sin is to die. That's why Suzaku is a soldier. That's why he fights. And he's ready to sacrifice himself whenever necessary.
If Suzaku had known in the past what he would become now, he wouldn't have believed it. Much had happened in the last few days, but the murder of Viceroy Euphemia had hit Kururugi especially hard. He hated Zero even more, and he was determined to kill him painfully, no matter the cost. But he couldn't comprehend that the head of the Black Knights, who had taken so many lives from his loved ones and innocents, would turn out to be his childhood friend, Lelouch Lamperouge. "Lelouch," is the first thing Suzaku says upon entering the cell. He immediately notices the prisoner's gaze. Many things could be read in his gaze: hatred, anger, regret, and a plea for mercy. Kururugi approaches Lelouch, who is sitting on the bed. He abruptly grabs him by the hair and pulls him down, slamming his face painfully into the floor.

After Japan was conquered and Suzaku killed his father, his personality changed dramatically. He decided he would not support terrorism or rebellion, which he believed would only lead to senseless killing. Unwilling to sacrifice innocent people, Suzaku developed a more positive view of Britannia, believing it could be changed for the better. He was also extremely loyal and never questioned his superiors' orders. Despite this, he was willing to stab them in the back if necessary. Suzaku also wanted to take responsibility for his actions, and his primary goal was to atone for killing his father. Although Suzaku never openly admitted it, C.C. and Lelouch concluded that Suzaku's greatest desire was to die, to rid himself of his guilt. But when Zero uses his Geass on Suzaku, when Schneizel corners them, forcing them to deal the killing blow, Suzaku turns into a man who desperately wants to die, but can't.
After Euphemia's death, Suzaku became determined to kill Zero and, by extension, Lelouch. He considered Zero an evil, immoral man, who cared only about the outcome and had no regard for innocent lives. Suzaku twice rejected Zero's offer to join him, even when Zero threatened him with a gun. Later, Suzaku continued to honor Euphemia's memory, striving to reform and become the Knight of Honor, earning the privilege of ruling the region himself and transforming the 11th region. He also kept the feather Euphemia had given him and adorned his Lancelot's shield with the Knight of Honor crest in her memory.