I was thinking about that when I designed him. His Crozius/Badge of Office IS the book. It contains powerful encantations that act as power weapon hits to enemies close enough to hear their utterance;(models locked in close combat). Perfectly game-legal, and more interesting than the "same-'ol, same-'ol".
Exactly, where is his badge of office? Such a high ranking member of the Adeptus Astartes would never leave it behind him! Very nice conversion indeed!