While Theo is still building his war party, Priscilla proves that Theo has the blessing of the Church, as well as the approval of the werewolves...and eventually the vampire-kin too. That technically puts him in direct opposition to the Union *and* the Alliance, who want to end the era of Chaos, while having both the blessing of the church and the approval of the chaos-kin, Theo proves that the Grandcrest itself is not needed.

The takeaway is Theo doesn't care about what you are, he'll help you regardless. The Church seems to consider that position worthy of their allegiance.

/random speculation