ReGan ("Regan" in the Crunchyroll translation of the anime; "Li Gan" in Yen Press' translation) is the Sage of Mirror Lake ("Sage of Miral Lake" in Yen Press' translation) and a dedicated researcher on magic. He first appears to discuss the world's magic laws with Shiroe, and later is invited by the Enchanter to travel north to Susukino with him.