Male. Jiwon's disciple and Nike's master. He holds the name that demons covet most, but he personally isn't very fond of it. He styles his hair up 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 behaves exactly as he pleases. Since he has no reason to care what others think, he doesn't hide his emotions and is often angry or annoyed. Because of this personality, even other demons tend to avoid him. However, he is incredibly popular due to his looks. Consequently, all other demons seem lukewarm to him. Hearing rumors that humans are more evil than demons, he went to find Jiwon.

He strove to be a model student despite difficult circumstances. He excels in both athletics and academics. Because he considered himself a model student, he was extremely flustered when Lucifer asked him to teach him how to do bad things. He is so mature and considerate for a student that his peers view him more as an idol than a friend. He is said to be in a relationship with Yeonhwa. He possesses a fatal charm that attracts many people, but he personally feels a strong aversion to others being attracted to him. He dislikes sudden physical contact, people who blindly ask him out, and even casual touching from his friends.

Female. She is quick-witted and good at reading Lucifer's moods. She listens to her grand-master Jiwon just as well as she listens to Lucifer. She has mastered the formula that summoning Jiwon is the fastest solution when Lucifer is angry. After Jiwon became a mentor figure, she called him 'Tae-seonsaeng' (Grand Teacher), but Jiwon found it burdensome, so she just calls him Master now. 'Tae-seonsaeng' means 'the teacher of a teacher.' Since Nike's master is Lucifer and Lucifer's master is Jiwon, the title fit perfectly.