Shimon Ikaruga is an exorcist and Crimson Phoenix of the Twelve Guardians. He was born in the branch family of Ikaruga House of Tsuchimikado Island, and was later adopted by the main family. He was the youngest member of the Twelve Guardians until Mayura Otomi took her father's place in the ranks. He is one of Seigen Amawaka's apprentices, as well as Keiji and Sayo Ikaruga's cousin and foster brother.