As always, interact with the site of lost grace as you enter the dungeon, and start going down the stairs. When you get to the first room, notice the two enemies further inside the room: one is hanging from the ceiling, and the other one is above the next doorway. As you enter the room, turn immediately left and there will be a third one sitting there to ambush you. Take him down, and the one above the doorway will come down, allowing you to defeat him easily before dealing with the one on the ceiling. Once they’re dealt with, proceed to the next hallway. Here, the tunnel will split into a path forward, and another one to the side. We’re going straight first (not down the stairs).
The path forward has a pressure plate on the ground that activates a trap. Additionally, at the end of the tunnel, there are two ranged enemies, and another hiding just inside the entrance that will leap out as soon as you approach the room. First, you will want to get close enough for the ranged enemies to notice you, and then go back to hide in the side tunnel, which will prompt them to come a bit closer to try and attack you. Now, run towards the pressure plate to activate the trap, and roll out of the way of the arrows to not get hit yourself.
Get close enough to aggro the enemies, let them walk forward a bit, then trigger the pressure plate and hide around the corner
This will take care of the two ranged enemies, and only the one on the left side of the doorway will remain. Once he’s been dealt with, use the lever and pick up the Root Resin. Then head back down the tunnel and take a left to go down the stairs. This next room has the same setup as the previous one: floor trap, plus two enemies on the far wall, and one hiding just inside the entrance (this one is above the doorway). Once you’ve dealt with them, head through the open gate to the Grave Warden Duelist boss fight.
If you’ve used up resources like Flasks or HP, go back to the site of grace and rest. You can sprint from the site of grace to the boss door without taking damage if you simply don’t stop running.
Unabashed FromSoftware fanboy still learning to take his time with games (and everything else, really). The time he doesn't spend on games is spent on music, books, or occasionally going outside.
In the first room there are two Grave Glovewort (1). In the room before the boss there is a Ghost Glovewort (1).
Gravewarden Duelist does not drop Great Hammer, it drops the Banished Knight Engvall spirit ashes.
Thanks for letting us know Moneyshirt, they keep moving items around on us! Apparently this was changed in 1.03.