Luciferianism

It makes perfect sense that they would choose luciferianism as their religion.

Madeline Montalban was an English witch who adhered to a specific form of luciferianism which revolved around the veneration of Lucifer, or Lumiel, whom she considered to be a benevolent angelic being who had aided humanity's development.

Occultism Luciferianism is a belief system that venerates the essential characteristics that are affixed to Lucifer.