They were Ormuzd and ahriman.
"The Beautiful Wretch; The Pupil of Aurelius; and The Four Macnicols"
William Black
Some trace in this the Persian demonology where the good spirits surround Ormuzd and where ahriman is the spirit of evil.
"Theological Essays"
Charles Bradlaugh
On many of his inscriptions the names of the old Mazdean pantheon, such as ahriman, the power of evil, still figure.
"Roman Society from Nero to Marcus Aurelius"
Samuel Dill