In Sacred Journey to Atlantis Dr. Norma Milanovich and J. Meltesen describe Hilarion as an "Ascended Master who is reported to be the Master of the Green Ray. This ray expresses the attributes of healing, constancy, and abundance." (SJA)
Ellie Crystal, too, calls Hilarion the Master of the Fourth Ray, the Green Ray of the Heart Chakra.
Many other sources, however, mention Hilarion as the Lord of the Fifth, i.e. the Blue Ray.
Edmund Harold quotes him both as linked to the Fifth Ray, as well as to the Yellow Ray.
He is linked to the Temple of Truth, which resides in the etheric realm.
Some claim that one of his previous incarnations would be as the apostle Paul, but this is contested by several authors.