An arch wizard who is descended from crimson demons; powerful humanoids who possess black hair and red eyes, and sport chuunibyou characteristics. Megumin only knows a single skill, the incredibly powerful explosion magic that immediately incapacitates her for the rest of the day when cast, and refuses to learn any other skills. (Source: Wikipedia, edited)

Reigen is a self-proclaimed psychic who exorcises evil spirits and leads a spirit council. He is also Mob's mentor and boss. He has a wide variety of skills and knowledge due to working a lot of different jobs. He uses them either when he helps his client or attacking his opponent.