When Lelouch Lamperouge formed the Order of the Black Knights, he took up the identity of Zero to lead them. Zero became a revolutionary and quickly gained popularity amongst the people who were against the Empire.
However, when Euphemia li Britannia the region under Mount Fuji the Special Administrative Zone of Japan, it effectively destroyed any possibility of the Black Knight’s rebellion. Acceptance would render them powerless and refusal would make them pariahs.
So what did Lelouch do? I won’t spoil it for those who haven’t seen the anime yet, but it was really a fascinating turn of events. Thanks to Ulysses for sending this in!