Hannah was a lowly Scribe who discovered that a Planetary Governor was paying tithes to a Slaaneshi Cult rather than the Emperor. When the cult tried to sacrifice her, she didn't pray; she audited the ritual. She realized the cult's "math" was wrong—they didn't "own" the souls they were offering. She hijacked the ritual, liquified the cultists into raw psychic energy, and manifested her "Hanavari" persona.
Now, she travels the galaxy with her retinue (including Milly and the ancient, cynical Inquisitor Alistair Graves), hunting daemons not with faith, but with bureaucracy.
Her Famous Quote:
"You claim this world for the Dark Gods? I have reviewed the metaphysical deed, heretic. Your paperwork is flawed. Asset... liquidated."
Inspired by @thebarwell sgt Barwell