Male. He bears the name most coveted by demons, yet he isn't particularly fond of it himself. He slicks his hair back because he doesn't want to look young. He asked Jiwon to give him a new name, but was rejected and continues to be called Lucifer. He is sometimes called 'Luci' for short. His actions are unpredictable, and he does whatever he pleases. Since he has no reason to care what others think, he doesn't hide his emotions, frequently showing anger or annoyance. Because of this personality, even other demons avoid him. Consequently, he finds other demons boring and sought out Jiwon after hearing rumors that humans are more evil than demons. He is currently running the counseling bar with Lee Jiwon and Nike.

Male. He strove to be a model student despite difficult circumstances, excelling in both athletics and academics. Because he considers himself a model citizen, he was extremely flustered when Lucifer asked him to teach him how to be bad. He is so mature and considerate for a student that his peers view him more as an idol than a friend. Possessing a fatal charm, he has many admirers, but he is said to feel uncomfortable with the fact that people are so attracted to him. He is currently running the counseling bar with Lucifer and Nike.

Female. She is quick-witted and excels at reading Lucifer's moods. She listens to Jiwon just as well as she does to Lucifer. She has mastered the formula that summoning Jiwon is the fastest solution whenever Lucifer gets angry.