Hierophantic

a. [ Gr. "ierofantiko`s.] Of or relating to hierophants or their teachings. [1913 Webster]

n. [ L. hierophanta, hierophantes, Gr. "ierofa`nths; "iero`s sacred + fai`nein to show, make known: cf. F. hiérophante. ] The presiding priest who initiated candidates at the Eleusinian mysteries; hence, one who teaches the mysteries and duties of a religion or an arcane discipline; an expositor; as, In his television series “Cosmos”, Carl Sagan became the foremost hierophant of modern cosmology.. Abp. Potter.
Syn. -- mystagogue. [ 1913 Webster ]

2. an advocate or spokesperson. [ PJC ]