In Anthem, who is the "Saint of the Pyre"?

Ayn Rand's Anthem is a novel which describes a dystopic future totalitarian culture. The lead character, named Equality 7-2521, witnesses a man being burned at the stake, whom he later describes as the "Saint of the Pyre." Equality 7-2521 gives him this name after he learns that the man was burned for discovering the Unspeakable Word, a word which Equality goes on to discover for himself.