When did Cordelia find out that Buffy was the slayer?
Cordelia officially realized that Buffy was the slayer in the first season’s finale called ‘Prophecy Girl’. Cordelia had known that Buffy wasn’t normal, in fact she was hoping she was in a gang at one point (‘Invisible Girl’), but the events of ‘Prophecy Girl’, where the Hellmouth tried to open with Cordelia standing right by it, was when Cordelia discovered Buffy’s true identity.
