Due to her biology, Android 21 has a natural, compulsive instinct to feed. Like Majin Buu, she prefers sweets and confectioneries, her favorite being macarons. However, she has no control over her hunger and constantly fights to keep herself from turning others into treats and devouring them. Her hunger is so great and painful that it has led to Android 21's psyche being damaged and manifesting a split personality. The longer she goes without feeding, the more the evil side of her gains control.