C.C. Appearances in Other Media-Nightmare of Nunnally

In the manga spin-off series, Nemo appeared in a capsule with on C.C. by its side and was picked up by Nunnally. When Nunnally was about to be killed, Nemo grants her a Geass ability that turns her body into Knightmare-like armor. During the process, C.C. sees Lelouch's plan to destroy Britannia with the newly formed Black Knights and acts as his double. In this continuity, it is revealed that once C.C. was known as the "Witch of Britannia" and was the rival and foe of Joan of Arc, known as the "Witch of Orleans", during the Hundred Years' War.

In Chapter 13, it is revealed that in this timeline, it was C.C. who killed Genbu Kururugi, not Suzaku; she did this to protect Lelouch and Nunnally, whom Genbu planned on killing.