The Untended Graves is a dark version of the Cemetery of Ash and Firelink Shrine.
Exit the bonfire area to collect the Shriving Stone and then turn left to find a Corvian Storyteller and three Corvians. It's best to defeat the Storyteller with ranged attacks first so that it doesn't cause the other three to transform and become highly aggressive and then finish off the remaining enemies to collect the Ashen Estus Ring .
A Soul of a Crestfallen Knight lies straight ahead and to the left you'll encounter a Cathedral Grave Warden and Starved Hound near a Titanite Chunk . Head down the stairs to encounter another Cathedral Grave Warden that patrols the center of the area and then pick up another Titanite Chunk near a group of Staved Hounds.
The watery path leads to two Ravenous Crystal Lizards that you'll want to split up, so pull one with a ranged attack and lead it back through the path to the open area. This'll give you more room to fight without having the second one join the fight and then you can defeat the other for a total of Titanite Scale x4 .
Continue toward and when you reach the area where the bonfire was in Cemetery of Ash you'll be invaded by the Dark Spirit Daughter of Crystal Kreimhild.
As the name indicates Kreimhild uses the crystal spells such as Crystal Soul Spear, Crystal Hail, and Homing Crystal Soulmass and she also wield a rapier that can be used for swift combos. Unfortunately, she has decided to spawn near a cliff that you can lure her to step off by circling around her so that she backs away from you toward the narrow path.
You can now clear out the standard Grave Wardens, collect the Hidden Blessing , and enter the boss arena where you encountered Iudex Gundyr.