Now that you have the Lordvessel after clearing Anor Londo, you want to head back to Firelink and towards the graveyard. These Skeletons can be tough to deal with, so be sure to go in with a crushing weapon such as a mace or club.On the way down are a few items, like the Binoculars and Zweihander- get those if you want them Now, head down the stairwell and into The Catacombs below.
Once down, you want to immediately be aware the enemies that explode on charging up. Head down further and you will encounter a few skeletons, these regenerate if you do not have a Divine weapon, there is also a necromancer who controls their undeath - kill that and they will stop regenerating.
With that in mind, head down the ladder. Head through the archway to the left, and then through the small opening in the wall to get to the Necromancer and a room with the Bonfire and Lever. Rest up, and pull the lever.
Now, there will be another path unlocked. Head back up and out into the open area, to your right is a necromancer, who you will be able to deal with if you have a ranged weapon. If not, you may have a tougher time chasing it down inside.
Then, there are 3 Skeletons ahead of you, take these out and head inside. Progress through here to a sairway heading up, then immediately to the right will be a Skeleton, in addition to the weapon Lucerne. Head out and keep progressing up, this is the best place to chase down the Necromancer, so do that ASAP.
Now, head to the left where the path splits. Go all the way down and kill the two skeletons next to the broken wall. There will be a Large Soul of Nameless Soldier, as well as a path back outside. Once again there will be a Necromancer across a bridge you can't get to yet, kill this from afar while you can.
There will be statues that protrude spikes if you linger there too long, so head right and be aware of the exploding heads and skeletons, that will knock you down to your death. There will be a lever at the end of this path, which we want to use, and then get the Soul of Proud Knight from the corpse and head back up and across the bridge.
If you head right and forward, you will fall down into a chasm below. We did this, so lets make our way back up. There will be a series of spike statues, so dodge through them and kill the Crystal Lizard on the way, if you can, then head up the ladder. Then, stand on the right grave to fall back down into the place where you previously pulled the lever.
So, push forward to progress. Head down the stairs and take out the necromancer at the bottom, then deal with the skeletons. Head further down the stairs, and but be careful as they suddenly stop. Go into the room with the archway and turn the lever. If you can angle the roll correctly, go for it and head down these platforms.
If you're looking for more help, our Dark Souls walkthrough and guide can help with all other areas of the game, including the dreaded Taurus Demon, Capra Demon, Ornstein and Smough bosses. Meanwhile, we have explainers on how to access DLC Artorias of the Abyss, the best gift and best class in Dark Souls, Dark Souls' best weapons, Dark Souls Covenants, Dark Souls Estus Flasks locations, Dark Souls Titanite Slab locations and NPC quests including Lautrec of Carim.
Drop down to he bottom through the hole in the floor, and you will reach a Blacksmith Vamos after a short cutscene. This smith is able to imbue weapons with Fire, so you can do so if you wish. Vamos will be able to use the Large Flame Ember, in addition to the Chaos Flame Ember, for the final upgrades- keep that in mind and remember where he is!
Head out and be aware of the Pinwheel Skeletons in this area, as they are able to kill you instantly if you get swamped. Head along the path and into the fog door for our next boss fight, Pinwheel.