New Londo Ruins (Upper)
You can access the ruins immediately upon your arrival at the Firelink Shrine but it's advised to wait until you need to kill its boss before you venture in too far. From the Firelink bonfire, face the Crestfallen Warrior (or where he used to be) and look to the left for a staircase leading down. Bypass Anastacia (ie. the woman behind the bars) and find a second staircase, also going down. This will lead to the elevator to New Londo. NOTE: This elevator will not reset if you die; you'll have to pull the elevator call lever to get it back up (so don't fall!)
- Ingward (Guardian of the Seal)
- Rickert of Vinheim (Magical Blacksmith)
- Witch Beatrice (Summonable Phantom)
- Hollow - they do not attack you unless provoked.
- Crestfallen Warrior (Hollowed NPC) - appears in the opening section of the area (before you cross the plank bridges) as a hollow if you talk to him after Frampt appears in the Firelink ruins.
- Ghost - floating ghosts with two sickles. They cannot be hurt or blocked unless using a cursed weapon (Jagged Ghost Blade, Greatsword of Artorias (cursed version made from Straight Sword +10), the player is cursed or under the influence of a Transient Curse. They can also hide in the walls and can flank you if you're not careful.
- Banshee - similar to the ghosts, but with a little more HP and a lightning spell. You can usually kill them before they attack you because they stop to scream when they see you.
- Darkwraith Knight - Once you access Lower New Londo, these powerful enemies will be down there waiting for you. They hit hard and can perform quick combos, but are slow to turn and are thus susceptible to backstabs.
- Mass of Souls - Also residing in Lower New Londo, these enemies are just giant blobs with faces on them. They have a lot of HP and attack by vomiting on you (a thick goo that slows your movement and slowly drains health. It also reduces the amount of HP your estus flask heals) or hitting you with their spear-like tongue. They can also create Wisps. They do not respawn once killed.
- Wisp - Spawned by the Mass of Souls, these disembodied floating heads will appraoch you once you get close and will then violently explode when they get in close proximity to you.
Once the lift from Firelink reaches the bottom, go down the stairs - beside the first flight of stairs you'll find a corpse with an item - until you reach an open area. This area is filled with Hollows who have gone crazy and are not interested in you, so you can ignore them if you want, but they're easy kills and are the only source of souls in this area, so whack a few on your way through. Go to the right first and you'll notice the doorway that leads to the Valley of Drakes - you should have come from that way when you were coming back from Blighttown earlier in the game. Go past the door toward the cliff and you'll see a Hollow laying on his side and to the left of him there is a staircase down to Blacksmith Rickert of Vinheim - he's behind some bars on the left at the end of the stairs. This blacksmith upgrades weapons to Magic and Enchanted status (if you have the right embers) and also sells a Catalyst for 500 souls, Soul Arrow for 2000 souls and Heavy Soul Arrow for 4000 souls.
Now go back to the entrance to the area and go left this time and you'll eventually find a doorway leading further into the area. Just inside this doorway you'll find the Estoc and further in you'll fight a hollowed NPC - the Crestfallen Warrior - if you rang the two Bells of Awakening and then talked to him back at Firelink (He's worth 1000 souls and can be defeated without too much effort). Continue on and you'll come across a corpse in a large pot, break the pot and he'll flop out and give you 2 Transient Curses - once equipped, these allow you to defend against and attack the ghostly inhabitants of the ruins ahead, but the effect doesn't last forever. ( Tip: Assign this item to one of your item slots to allow you to check quickly if the item's icon is greyed out or not. If it is then you are still affected but if it's not then you'll need to equip another before you can take on more Ghosts) Equip a Transient Curse and then go across the wooden bridges to enter New Londo proper. Look on your right as you cross the second bridge and you'll notice an item out in the water, we'll get that soon.
As you get to the end of the bridges you'll start to see the ruins you're about to traverse in the distance and you'll likely notice the two figures slowly floating toward you - these are Ghosts, and you should have a little info on them before you continue. They are floating apparitions of the previous inhabitants of New Londo, before it was flooded, and they attack using two jagged knives, but the most important thing to note is that they cannot be hit and you cannot defend against them unless you are either cursed, affect by a transient curse or have specific weapons equippied. Also, be aware they can pass through walls and floors to attack you, so don't rush into an area thinking there are no enemies as they can very quickly come out of the walls from all sides and surround you if you're not careful. They have some quick close-combat slashing moves which can all be defended against with a shield and they also have a longer range grab attack, but you can avoid it by either running straight at the Ghost performing it or run/roll out of the way of their knives. It's advised that you take your time as you travel New Londo to avoid Ghost ambushes, learn their spawn points and aggro as few of them as possible at once.
So, back to the walkthrough, with the transient curse equipped you should be able to defend against the attacks of the two Ghosts ahead of you and defeat them. Turn around now and you'll be able to access the item out in the water we saw earlier by finding the thin walkway hidden just under the water, but as you cross it you will see a few more Ghosts appear around you. When they appear, go back to the larger area of land to take care of them before proceeding the rest of the way across. The item at the other end is a Fire Keeper Soul, so it's well worth the effort.
After that, go to the other end of the area on the right side and look behind a wall close to the edge to find a pot with a corpse holding another two Transient Curses. ( Note: this is also the place that provides quick acess to lower New Londo after you lower the water level, so make a note of the location as you'll likely use this shortcut). Now go to the left side to find some stairs. Immediately upon clearing the staircase, the landing ends inside a ruined building. Rather than walking to the very obvious bridge, go right until you see a single Ghost spawn. Defeating it and then then move towards the bridge to trigger a second one. Before going across the bridge, use arrows to take out the Ghost that's floating above the catwalk on the right - it'll make it easier to get the item there later. Now, move across the bridge to enter the first of the areas towers.
Once across the bridge, you'll see a Ghost waiting inside the tower ahead. She is bait for two traps: (1) a single Ghost will attack through the walls on the left as you go to enter the room. Keep your shield up as you approach the room to take on this Ghost with-out getting hit and note the elevator and lever behind her - they don't work yet, but they will once you lower the water level. (2) As you then enter the room at least four more Ghosts will come out of every wall - including one that will emerge from the floor behind you, blocking you in. So, walk into the room until you spring the trap and then immediately run back out the way you came. If you're quick, you'll step right over the Ghost that means to box you in, but you should simply take this one out should she manage to get in the way and run back to the bridge. The other Ghosts from the trap will line up while following you onto the bridge, making it easier for you pick them off.
Go back into the room and it will lead you to a spiral staircase that will take you down one floor. Straight ahead at the end of the ledge is the Parrying Dagger, but before picking it up you should be able to see the arms of the Ghost waiting in the wall on the left of it - be sure to take it out before you pick up the item. Back to the start of this ledge and take a right, there's a Ghost in the floor, a fog gate on the right, and a Banshee around the corner ahead guarding another two Transient Curses. Be careful, Banshees are like Ghosts but have a little more HP and a ranged lightening attack. You'll know it's a Banshee and not a Ghost due to their red face and they're usually easy to take care of because they stop to scream when they see you, leaving them wide open for attack.
Through the fog gate you'll climb a staircase that will lead you back upstairs, outside and onto an elevated catwalk. At the first corner, be sure to kick the ladder here and go down. There are two Ghosts down here behind the pillars on the left who would have attacked through the floor as you walk above, so getting rid them first is ideal. Once back at the top of the ladder you'll see an item (a Soul of a Nameless Soldier) at the end of a ledge close-by. If you shot the Ghost earlier on then feel free to go and get it, but if you didn't then be prepared to be attacked from above as you approach the item. Now continue across the catwalk.
After crossing the catwalk, you will see a second square tower ahead and as you walk around the tower towards the doorway leading in, look down and to your left into the water. The instant you see Ghosts moving towards you, go back up onto the catwalk. Two Ghosts will come through the walls of the tower to attack you, but if you back up just enough you should pull only these two - leaving four more in the water. Ensure you pick off the remaining ones in the water before going inside the tower - if you don't, and simply run into the tower, you'll be attacked on all sides - you should be able to lure a couple out of the water at a time back onto the catwalk.
Once there are no more Ghosts outside, go into the tower. Inside there's a door with some downward stairs to the left and another door ahead that goes into a room containing a Banshee and a pretty transparant trap. Ignore the door with the stairs for the moment, enter the other door and be prepared to take out the Banshee quick before the rest of the Ghosts appear. Once the Banshee is dead go back out the door to get the other Ghosts to follow you out for easier dispatching. In the room where the Banshee originally sat there's a ladder in the fireplace that will take you to the roof to meet Ingward. He sells Transient Curses (ensure you pick up a few), the Resist Curse spell and can also cure the cursed status. If you got the Lordvessel at the end of Anor Londo he'll give you the Key to the Seal when you talk to him, but if you don't have it yet then you can also simply kill him to get this key - ensure you buy what you want from him before you kill him though.
Now go back down the ladder and go to the door with the stairs leading down. As you go down you'll see a door on the left that goes back outside, but we'll come back to that in a minute. Continue on and you'll traverse a few narrow corridors with Ghosts that are lying in wait in the walls and floors, so proceed with caution. If you make your way around you'll find a door that goes out onto a ledge with a corpse, but moving toward it will spawn another Ghost on the left side of the ledge. Defeat it, loot the Cursebite Ring from the corpse and then go back to the door we passed by earlier on and go right once you get outside. There's stairs going down to the left and up to the right out here - going down to the left will lead to a corpse holding a Green Titanite Shard, but beware of Ghosts guarding it. Now go up the other stairs to find a ledge leading into another tower and another stairs going up, but we'll go up the stairs for now. You'll find Humanity at the end of the ledge up here and you'll also have the opportunity to jump onto the side ledges of the second tower's roof to collect a Rare Ring of Sacrifice. Once you get it, look around for a window to get back into the tower - when you go through you'll be in or near the room with the ladder that goes up to Ingward. Now make your way back to the ledge that leads into the tower we haven't entered yet.
In here is a spiral staircase. Go up the stairs and along the ledges to find a corpse with the Composite Bow and some Large Arrows. Going down you'll find a currently non-functioning lift and a locked gate which can be opened with the Key to the Seal you got from Ingward. Inside this gate is a large lever that, when switched, opens a very large door that lets the water drain from the flooded Lower New Londo. With the water drained, Lower New Londo is now accessible via the elevator near the seal lever.