In case you didn't know, the only way to figure out the dark souls lore is to think deeply *facepalm*.
And the shrine handmaiden actually has access to all of the boss rooms anyways. Firelink shrine is right there and every boss has a bonfire in their boss room. If you need souls to stay alive, but your *** your gonna climb out that chair, hit that bonfire as soon as a boss drops, and start scavenging. After all, Bosses don't respawn so it's not like she'd actually be in any danger.
Hell, the hag from DS2 couldn't swat a fly but she had the freshest, dead folks outfits.