Word Bearers have an organization and follow a combat doctrine not far removed from the Codex Astartes (that doesn't mean they've adapted Guilliman's work, just that they follow the old ways). Since the Heresy their Chaplain's have surplanted the other officers. So a Word Bearer Company is not commanded by a Captain, but by the Company Chaplain. Line officers still exists, at least in some formations, but they are first and foresmost tactical advisors and executive officers, not leaders. Host = Chapter. Apostle = Chaplain. There are several ranks here - not all Apostles are equal. The greatest of them is Erebus. Castor ranks pretty low, but his star is rising. Acolyte = Apostle-in-training. Apostles are expected to search the Legion for promising candidates; all Word Bearers are religious fanatics, but all are not equally well suited to the twin roles of leadership and spreading the Word. First Acolyte = First among an Apostle's acolytes. To be named one is a great honor. Some First Acolytes are expected to act as second-in-commands, while other Apostles prefer that their wards focus on religious matters. Coryphaus = Ranking non-Apostle within a Word Bearer formation. The equivalent of a Captain or Chapter Master. He is also the 'voice of the congregation'.