The Fourth Neck (四の首, Shi no kubi), she is a delusional pop idol whose dismal sales (68th, though Reiko constantly taunts her with "69th") are partly responsible for her becoming one of the Orochi. She is almost manic in her behavior, constantly trying to impress the other Orochi with her showmanship, but her energetic exterior hides a dark past.

Spoiler

Corona's flashback scene may indicate that she had to have sex with someone to get her first big break in show business. It is likely that the event involved considerable violence and left Corona emotionally damaged.

(from wikipedia)