Word cubed. Also, the title of the show and comics is Buffy the Vampire Slayer, which means the one character fundamentally required is Buffy. Anybody with their nose out of joint because their favorite deceased character hasn't been resurrected, or because one character who died in the final televised episode and was brought back and made a regular on another show but hasn't suddenly materialized and started hogging the spotlight of BtVS once again, needs to realize that.