Sen's Fortress is dark castle filled with monstrous reptilian guards, boulder throwing giants and numerous traps such as massive swinging axes, massive boulders and other encouraging aspects.
It serves as the gateway to Anor Londo.
- Big Hat Logan - After breaking a hole in a wall with a boulder( note the wall can be broken by hitting it with your weapon), you'll find him in a cage that can be opened with either the Master Key or the Cage Key that you find in the area.
- Crestfallen Merchant - The merchant can be found across a broken bridge after reaching the rooftop. You must run and jump across to make the gap.
- Siegmeyer of Catarina - He can be found outside the gates before they open and once they are you can find him near the first rolling boulder section.
- Iron Tarkus (Summonable NPC) - His summon sign is found in the tower across the bridge nearest the boss' fog gate, but only if you are in human form. He helps greatly during the boss fight.
- Serpent Soldiers
- Serpent Mages
- Undead Knight of Balder (Rapier and Buckler, Sword and Shield, Ranged)
- Titanite Demon x4
- Firebomb Giant (3000 souls, Titanite Chunk)
- Gate Giant (3000 souls, Titanite Chunk)
- Rock Giant (this one respawns)
- Tower Knight
- Ricard the Archer
- Mimic (drops Lightning Spear - the weapon, not the spell)
The Entrance & Ground Floor Sen's Fortress is found through the door beside the bonfire that's above Blacksmith Andre in the Undead Parish. The gates are locked tight when you find the area initially and you'll meet Siegmeyer of Catarina outside, waiting patiently for the gates to open. To gain access you must first have rung the Upper and Lower Bells of Awakening, which prompt a Giant to open the gates. If you haven't rang both the bells yet, you're not going to get in.
The first room contains two Serpent Soldiers who can pretty easily be lured individually by keeping a pillar in between yourself and just one of them. Beware of the arrow trap triggered by a button on the floor - it will fire three arrows out of a slit in the middle of the central staircase. With a bit of luck, you can keep one of the Soldiers between you and the trap, which will kill him. In the top right hand side of the room, there's a soul item on a poorly hidden corpse behind a few pots.
In the next room you'll see an out-of-reach item up on a ledge on your left, a large pit with a thin walkway to cross it and you'll also be introduced to the Sen's fascination with swinging blades, which make the walkway more challenging to cross. The blades are fairly simple to avoid if you're willing to be patient. However, there's a Serpent Soldier behind the first few blades and a Serpent Mage casting lightning spells from the walkway above, which makes things even harder. Before going through the swinging blades, you can engage the Soldier with an arrow and get him to walk towards you and through the blades (hopefully killing him), and you can also reach the Mage with arrows from here too - a few well placed arrows will knock him from his perch and he'll fall to his death. No bow or arrows? Well then, you could just go ahead through the blades and fight the Soldier on the narrow walkway, but it's usually easier to simply walk back through the swinging blades after you get his attention because they are bad at avoiding them. Beware that getting knocked off the platform may not kill the Serpent Soldier ahead of the blades, and if he survives, then expect him to eventually jump down from the ledge with the out-of-reach item you saw earlier - he should have low health at this stage and shouldn't prove to be too much of a problem.
The Pit NOTE: You can go down into the pit here to kill some strong enemies, get souls and some items if you wish, but it can be difficult. If you want to skip this for now and come back here later, then skip the next paragraph - otherwise, read on.
Look down and you'll see a Titanite Demon directly below you on the right side of pit - luckily you can also target him from up on the ledge. Once targeted, you should be able to easily take him out with ranged attacks if you stand close to the edge. Once he's dead we're going to drop down off the edge into the pit, and the fall will take off a great deal of health, so be sure to heal yourself before you drop down. Once down there you'll find the ground covered in a tar-like goop that limits movement - equip the Rusted Iron Ring to allow easier navigation of this pit. Down here you'll find four Titanite Demons - if you killed one as per the start of this paragraph, then that leaves three - these Titanite Demons do not respawn once killed. Go forward toward the row of three pillars and beware of the three Serpent Mages up on the ledge at the end - you should be able to take them out with arrows while remaining far enough away so their spells cannot reach you. Continue forward toward the pillars and you'll see another Titanite Demon in the tunnel behind them - with the pillars in the way, this guy should prove to be an easy kill using ranged attacks - in his tunnel you'll find a Large Soul of a Brave Warrior and the Scythe . There's a passage on the right side, near the pillars, that leads to a long, wide corridor with two more Titanite Demons - there's nothing else down there, though. These two demons can also be easily taken out with ranged attacks from within cages in the same room as Big Hat Logan, who you can choose to encounter later. If you want to get back out of the pit, there is a room in the corner next to where you initially dropped down, with a ladder back up. Once at the top of this ladder, you'll now be able to pick up the out-of-reach item from earlier, and if you hit the blocked-up archway up here you'll reveal a secret ladder to the top of the fortress where you can kill the Giant that opened the gate. Now go back down to the ledge where you found the first set of swinging blades.
Traversing the Fortress and its Traps Continue past the first set of blades, up the stairs and across the walkway with more swinging blades, confronting the Serpent Mage if you did not already dispose of him. There is an arrow trap before the chest, just as you enter the room - three arrows will be shot but keep your shield up and you should be fine. Continue onwards and you'll see a sleeping Serpent Soldier leaning against a wall on the walkway below - if you wish to rescue Big Hat Logan, leaving this guy alone can help with doing so later; further instructions are below. Continue forward and you'll see a door leading outside, but don't rush out. Be careful, as large boulders are rolling from the left and down the ramp outside, and there's also another Serpent Soldier out there too - but the boulders should take care of him. Time it well, take a left up the ramp and sprint to the door that's on the left with the fog gate, but don't go through yet. You can go up further to find a Serpent Mage at the top of the ramp. If you have a bow and arrows you can peek out of the first door before you try running up the Boulder ramp. You can see the Serpent Mage in the doorway just under where the boulders come crashing down. Take aim and hit him to get his attention. Be careful to do this just after a boulder passes your doorway so you don't get hit. He will come after you down the Boulder ramp and get flattened. In the building behind him you'll find a chest holding the Ring of Steel Protection. After this, leave the building and hop off the side of the ramp to the left to find a weapon - the Shotel. Then hop down further to meet two Serpent Soldiers and Siegmeyer of Catarina again - take care not to hit him if you want to avoid a tough fight and continue his quest-line. Go to the end of this area to find a way back up the ramp, and time it so that you can sprint up and into the door that you initially came out of, and then do this again to reach the second door with the fog gate once more. Now go through the fog.
In here you'll find an empty room, but in the corridor it leads to there's another arrow trap, this time shooting you from behind. Step on it and turn around with your shield up to be safe. There is a Serpent Soldier on the left in the next room. After that, slow down - more boulders are passing by the next door. Let a boulder pass by and then chase it down the winding ramp (although be careful not to run into the boulder, as even though it is rolling away from you, touching it still registers as it hitting you), avoiding the spells of the Serpent Mage that's on the rafters above. Keep following the ramp down until you reach the hole in the floor and take the door on the left to avoid the next boulder coming down behind you. You can head into a secret room behind the hole, but you'll have to wait for more boulders to fall in and fill it before doing so. Once it's full, wait for one more boulder to knock a hole in the wall and follow immediately after it, taking a sharp left as soon as you can. You'll notice a corpse hanging on a window close-by; loot it for the Covetous Gold Serpent Ring, but be careful not to get smashed by the next boulder. There's nothing else in here, so go back the way you came in and take the door on your right.
The noticeably askew chest on the ground in the next room is a Mimic - don't open it! This is likely the first time you'll meet one of these, so take note. They look exactly like normal chests but are actually quite powerful enemies, and upon opening them, they'll either eat you whole or take off a big chunk of your health. Take it as a rule of thumb from this point onwards that you should always give chests a whack, or ideally a strong attack, before attempting to open them. If it's a mimic, then this will become immediately obvious and you'll have to fight it off or run away. If you ignore them, they won't become hostile and will simply sit there waiting for you to open or attack them, but ignoring them will not allow you to get the valuable treasure they always hold - for example, if you kill this one, you'll be rewarded with a Lightning Spear. Also, there's a lift in this room, but beware of the rather devious trap it holds. As it goes up, it'll stop for a moment at a point where you can get off - ensure you do so. If you don't get off in time, it will go up further and crush you into a spiked ceiling. (NOTE: If you need to take this lift down later, wait for it to go up into the ceiling and come back down again before you get on) From there, go up the stairs, across the bridge, then go down the following stairs and run up the ramp to find the room with the boulder aiming mechanism.
The Boulder Aiming Room You can send the boulders where you like at this point. There is a platform in the center of the room with a lever to rotate it, allowing you to aim and fire boulders through one of four openings on each side of the room. Turn it counter-clockwise once to fire the boulders down to where you saw the sleeping Serpent Soldier from earlier. Let a few boulders go down this way and then turn the lever counter-clockwise again - if you ignored the sleeping guard from earlier, then you'll know when to turn the lever again once you collect the souls from his death. If you don't have the Master Key, then you may as well skip to the next paragraph - otherwise, read on. Go down the path where you were just firing boulders and you'll see that they have made a hole in the wall that you can pass through. In the resulting room, you'll see various hanging cages on either side of the walkway. Near the end, you'll see Big Hat Logan locked in a cage on the right side, and you'll also find a Soul of a Hero in a cage to the left side. Other cages, when opened, can be used to range attack the two Titanite Demons in the tar-pit below. Talk to Logan, and then use the Master Key to free him and obtain the soul in the other cage. If you don't have this key, then neither cage will open for you right now, and you'll have to come back here later once you have obtained the Cage Key. You'll now have to make your way back up to the boulder aiming room to continue.
Change the direction of the boulders to allow you to go down the path with the winding ramp that you chased a boulder down earlier. Taking this path, hop right off the side of the stairs from the highest point you can do so and you should land on a ledge with the Serpent Mage who was shooting at you while you were chasing that boulder earlier. After dispatching him, collect the Soul item and go towards the archway in the wall you just dropped from. Enter in, find the Black Sorcerer Set (along with the spell Hush) and go back out the hole again, and to the other side of the ledge and find the window. Be warned; it's a long way back up, but if you go through the window here and drop down, you'll find the Slumbering Dragoncrest Ring on that floor. You can make your way down from here through a hole that has a series of ledges along the sides of it that you can drop to, and at the bottom you'll be in the tar-pit. If you didn't clear out the Titanite Demons from down here earlier on, then either get your Rusted Iron Ring out and run or prepare for a fight. Make your way back up to the boulder aiming room again.
The Journey to the Roof Back in the boulder aiming room, in addition to the four large openings you can shoot boulders through, there is also another, smaller passage. Go down this passage, but be careful of the arrow trap; this time 4 sets of arrows shoot 3 arrows from the left. Don't try to run straight through, just trigger them via the switch on the ground and run back out of harms way until they stop firing. You'll then be greeted by another set of swinging blades along another thin walkway. For this group, sprint through them all in one go and try not to fall off. (You may find that rolling through them is better, if you are particularly slow due to heavy armor and the like. Just be careful, and watch your timing.)
In the room at the other side of the walkway, there's a Serpent Soldier down a corridor on the right with a hole in the floor behind him, so be careful. (However; you can use this hole to access the pit if you haven't ventured down there yet.) Turn around and you'll see a staircase with a Serpent Mage at the top. Take care of the Mage, but don't go up there yet - take the passage to the left of the stairs first instead to find another Serpent Soldier and an item. Now go back and up the stairs, and you'll see the final set of swinging blades on the thinnest of the walkways, but before you take them on, you should take out the Serpent Mage to the left of the walkway with ranged attacks. To get past the blades here, take them on in pairs. After you get past them, you should see a fog gate to your right up some stairs and a path to the left to where the Mage was that you just killed. Also be aware of the two arrow trap triggers, one on either side - the arrows come from the left if you trigger either switch. Go through the fog gate and you'll find yourself on the roof of the fortress.
The Rooftops Once on the roof, you'll see the Rock Giant straight ahead of you - he's the one that's been dropping boulders into the boulder aiming room. He's harmless, but if you want, you can kill him with arrows (he respawns though). If you head to the right, there are two Undead Knights, and there is a chest with the Flame Stoneplate Ring, but you'll get an opportunity to get this later if you want to leave it for now. If you go the other way and up the stairs, you'll be greeted by some huge firebombs. The Firebomb Giant on the roof is hurling these down at every chance he gets until you get to him. After one explodes, wait for the flames to subside and then run quickly up the stairs and also the second flight of stairs ahead of you. Up here you will notice a corpse on the floor - he is holding a Large Soul of a Brave Warrior - and if you look to your right you will notice an opening in the wall - drop down here to find the only bonfire in the area. Make your way back up and then ascend the third flight of stairs where you'll see another corpse holding a Large Titanite Shard. Going straight leads you to a Tower Shield Knight with a mace who hits pretty hard, however; he can be taken out using arrows without getting his attention by standing before the stairs leading down to him. Go past him and to the left, descend the ladder and go straight toward the tower ahead where you will be attacked by Ricard the Archer as you climb the stairs - he's an easy fight and drops Ricard's Rapier. Past him you will find two chests holding a Divine Blessing and a Rare Ring of Sacrifice.
Head back the way you came - where you found the second corpse with the Large Titanite Shard. This time go up the stairs to the left and you'll find yourself on an elevated walkway - beware that the Firebomb Giant can still throw firebombs in your way on this walkway. The path splits into two here with a jumpable gap on the left side that you should ignore for the moment. If you take a running jump off the walkway and straight forward towards the Rock Giant you will land safely on the ledge of his rooftop. Turn around, look down and at the bottom you will see a corpse - drop down here to find a Sniper Crossbow and some Sniper Bolts. From here jump down to find the Flame Stoneplate Ring and Undead Knights you may have ignored earlier. Make your way all the way back up to the walkway again, ignore the jumpable gap on the left again and take a right for now where the path forks yet again once inside the building. Left is an Undead Knight (you can safely ignore him) and a dead end, he guards a vagrant spawn point. Going right leads you into a room with two hanging cages in it, but without the Cage Key you won't be able to open them - we'll get this key soon. Once you get the key, open one and get inside, it will take you down to the first room with the swinging blades - opening up a valuable shortcut that by-passes a lot of Sen's Fortress. On the other side of the room with the cages, you'll find a door leading outside again and up to a thin walkway that turns two corners. There's an Undead Archer firing at you here and the Firebomb Giant can also throw bombs in the way. You'll have to be quick about traversing the walkway, but follow it around without falling off and you'll be face-to-face with the Archer if you didn't kill him already - he's a non-issue up-close.
In the next room, you should see the fog gate which leads to the boss - you can look out the windows beside the gate to get a early glimpse of him if you want, but we'll leave him for a little while until we sort out the last few things in this area. Also in this room you'll see a doorway to a bridge and staircase going up. If you take the stairs up, you can finally kill the Firebomb Giant. To defeat him just stay close behind him, hack and slash at his legs and back away when he starts to do his stomp move. He does not re-spawn once he's killed. Once you have disposed of him you can wander the fortress rooftops safe in the knowledge that no more firebombs will get in your way and with that in mind you should head back to the jumpable gap in the walkway we ignored earlier. Make your way back to it and take a running jump over the gap (being under 25% equip load here will help make the jump easier), continue onwards to find the Crestfallen Merchant inside the tower. Go down the stairs from here to find a Serpent Mage on a bridge. Behind him you will find a corpse with the Cage Key, which will allow you to access a soul and free Big Hat Logan (if you didn't have the Master Key already) and unlock the two hanging cages for the shortcut mentioned above.
With all that done, now it's time for the boss. Make your way back up to the room at the top of the fortress with the fog gate; but If you're in human form, don't go through the fog gate yet. Instead go through the doorway to the bridge and run across to find a room where you can summon Iron Tarkus to help with the boss fight. Now go through the fog gate.
Boss Fight: Iron Golem
After the boss fight, you'll see a glowing orange ring in the centre of the arena. Touch the ring and you'll be treated to a cut-scene where you're carried away by three Bat Wing Demons who safely deliver you to Anor Londo. If you want to get back, turn around and talk to the bat wing demon perched on the wall, and you'll be taken back to the Sen's Fortress boss arena. Otherwise, it's time to traverse Anor Londo