Horigome is the classical literature teacher at Sakuragaoka High School, where he has taught for a long time. He was the supervisor of the school's light music club when the members were a band known as Death Devil. He considered the club too wild at the time, experiencing many problems and frequently scolding the members. He continues to teach, but is no longer the club advisor.
She is a friend of Sawako's from back when they were in high school, and they were both in the light music club together as part of the band Death Devil. She and Sawako used to try to outdo each other on the guitar. Her stage name is Christina.
Balar is a Crimson Lord who is contracted with Rebecca. He expresses his will through a divine vessel called the Cruach, which takes the form of a golden bracelet worn on Rebecca's right wrist. (Wikipedia)
Centerhill is the Native-American Flame Haze who, with other three, are known as the Four Gods of Earth. He and Tlaloc, his contracted Crimson Lord, are widely feared by many Denizens; but only few know of his unique power, the Tlalocan. Centerhill runs one of the Outlaw branch in the United States after the clash between the Four Gods of Earth and fellow Flame Haze known as the Civil War. (Wikia)
Uvall is a Crimson Lord and a member of Bal Masqué.
Gyuuki is a Crimson Denizen and the leader of the Hyakki Yakou. He usually takes form of a lion dance equipment with wooden body which is covered by long cloth.