Divine Vengeance does not charge extra MP for Words if the Archon is using one of their innate attacks (Blade of Light or Eye of Judgement). Additional Words from Celestial Chorus still require additional MP/Word.
Makes using Words more appealing since one of them is a freebie. No longer will a Level 20 Archon drain their MP reserves after a mere 9 attacks with Eye of Judgement and a Word activated, and Blade of Light will now suck slightly less.