Swap in Lingering Dragoncrest to cast buffs, swap Havel's Ring back in, then go to town.
Spam dat Obsidian R2.
You can use Chameleon to get the drop on people to help conceal the cast animation (or swap it out for Dark Bead/Black Flame/Crystal Magic Weapon/Power Within).
Swap in Grasscrest Shield and Moonlight Greatsword as desired.
Sanctus is there to help offset Power Within HP drain (regen works even if you don't meet the Faith requisites).
