At the top of the Cathedral Ward resides Vicar Amelia. Upon encountering her, you'll see her transformed into a horrifying, bandage-wrapped wolf monster. Yikes.
For as horrifying as she looks, Amelia can be taken down quickly if you're careful. When close, she'll attack with all manner of claw swipes and palm slams. Sidestep these, and use the moment after she attacks to deal some damage of your own. Stay locked on to avoid getting turned around in the relatively narrow chapel. Should you find yourself far from Amelia, use a sidestep to avoid her long-range pouncing attack.
The only real trick up Amelia's sleeve is healing herself. Use this time to deal as much damage as you can, counteracting the amount she'll recover. Soon after, she'll likely enter a rage state. Don't attempt to attack her when this happens - just stay back.