Quelaag once lived with her mother, the Witch of Izalith, and her siblings in the ancient city of Izalith. After the Flame of Chaos incident, all but her sister Quelana were transformed into nefarious demons. She and one of her sisters escaped the worst of it, having their lower torsos bound to giant spiders. Fleeing their deranged, demonic kin, they climbed to the base of Blighttown and Quelaag fashioned themselves a home.
More accurately, at the end of Blighttown. Quelaag's Domain's entrance is behind the three boulder-throwing Infested Barbarians at the Blighttown swamp.
- For phantoms helping a host, equipping the Orange Charred Ring has no effect on Quelaag's lava damage.
- Lava stream - Slow buildup, long-lasting. Quelaag's spider-mouth spews a solid stream of lava left to right. Telegraphed by the witch pushing the spiders head down for a while.
- Lava glob - Quick attack. The spider-mouth lowers and spews out a small blob of lava right under it. Telegraphed by the witch dipping the spiders head quickly.
- Lava spit - Quick attack. Small blob of lava shot a distance away from the spider's mouth, followed by Quelaag leaping to the side. While up close, this attack will look similar to the longer lava-spewing attack, but differs in that the glob is not followed by a solid stream of lava, but rather thinner, seethrough lava that doesn't settle on the floor.
- Side stomp - Long buildup. The spider raises its legs on one side of the body, and then stomps them all down on one side of Quelaag's body for high damage. Even if not hit by the stomp itself, small shockwaves erupt from the impact points, doing fire damage and making it hard to punish the attack if it misses. Telegraphed by the spider leaning back on its hind legs for a while.
- Lava spray - Quick attack. Spider will light up and send fireballs in all directions.
- Lava sideswipe - Attacks may be followed up by a quick, solid stream of lava in a quartercircle to the side of Quelaag's body. Seems to be in response to the player being on Quelaag's side.
- Lava pounce - Used when the player is at medium-long range. Without a doubt Quelaag's most dangerous attack. Spider lowers its body and then jumps quickly forward toward the player, spewing a quarter-circle of lava that lands in front of where it lands. If the spider lands on you, it does high damage.
- Roar - The Spider will occasionally roar. It will do the attack much like the stomp except without the legs lifting into the air. This move is very damaging and sometimes will be chained together with the spider's lava spew or a strike from Quelaag's sword.
- Flame Aura - Slow buildup. The fire on the spider's abdomen brightens as she slumps forward over the spider's head, charging up a high damage AoE attack. Usually follows a Lava stream attack if the player is behind her.
- Firesword swipe - Quick buildup. Raises her sword, striking horizontally in a circular pattern. Can easy be avoided by circle strafing or walking backwards, thus saving energy for a shield block.
- Firesword stab - Medium buildup. Quelaag raises her sword, stabbing straight ahead with huge fire damage, can be avoided by circle strafing or rolling backwards.
- Sword combo (3 moves) - Performs two Firesword swipes followed by a Firesword stab. Similarly to other enemies Quelaag will stop the combo if the player is too far away.
Dodging and Blocking
- Human: Quelaag's weapon deals a mixture of fire and physical damage but is easy to block. A shield with high fire resistance is recommended, the Black Knight Shield or Dragon Crest Shield are good choices, especially when paired with Flash Sweat. To dodge, roll back from her swipes and to the side from her stab, or you can simply run out of range. You can also get under her attacks by running up against her, however always run away when you see her start her flame aura, she often uses this if you try to attack her after she finishes a weapon attack.
- Spider: You should not aim to block her spider half's attacks. Just keep her in sight while she chases you (don't lock on) and run to her side whenever she uses a lava attack. Beware of her pounce attack! Stay close where you can and if she uses this, immediately run back, if she hits you with the lava it will nearly always kill you.
Note she may use her pounce attack upon engaging you after you enter the fog gate. Again you should run back and then around the lava to get in close enough that she does not use it.
Your best window of attack is when she uses her spewing lava attack. It has a long channel and does not track you.
All of Quelaag's lava attacks leave a varying (depending on the attack) amount of lava globs on the floor. These do a lot of damage if stepped into as well as slowing your movement speed. The globs disappear after a while, fading out as they do so, but keep a close eye on your surroundings and try to lead her to "clean" areas. She seems to attack more frequently on lower life so beware of increasing amounts of lava on the ground.
The Rusted Iron Ring is useful if you have a spare ring slot as you will be able to run through the lava without being slowed (although you'll still take damage).
Try not to get too close to the walls, it's not too big a deal but with such a large arena there is no reason to limit your movement, especially with lava globs involved. You can also, in a few places, become pinned against the wall.
It is possible to get Quelaag stuck on the environment. As soon as the fight begins run to the door up the small bit of stairs in the back of the room, the right corner is just far enough to cause the boss to become stuck trying to run towards the player, although she may still use lava attacks.
Your safest strategy is to bait out her lava spew attack, then run around her and attack her back leg. This requires her to turn for all but her flame aura (watch for this) to hit you, allowing you to get out of range again. Do not confuse her lava spew with just spitting a gob of lava as that attack is much shorter.
- If you're close enough and want to play a bit riskier, the lava glob attack (a glob of lava forms directly underneath the spider-mouth), and the long-distance lava spit attack (while close, look for a glob being shot out of the spider's mouth followed by thinner/see-through lava) provide short windows for an attack or two. Do not try any long combos here; with the short-distance lava spew, Quelaag may immediately follow up with another attack; with the long-distance lava spit Quelaag will jump away to the side before you have time to do anything more.
- For an additional window, get in close to Quelaag as she starts swinging her weapon, all of her swings seem to have a blind spot on her left (between the spider's head and foreleg) allowing you to attack once each time she misses (slow weapons not recommended). Once the combo is over she will usually hop back and retreat. Note you can stun her this way and the spider will start attacking you so retreat if this happens.
- A large weapon with an overhead attack such as a Halberd will hit her human body and stagger her. You can keep her staggered until you run out of stamina. Timed right you can keep her staggered the whole fight making it an easy battle.
For headshots, Quelaag's human half is considered a "head". With a strong ranged attack you can stagger her but keep your distance and watch for her pounce.
Status Effects and Items
Shooting Quelaag's human half with a Great Soul Arrow (Soul Arrow or a strong arrow from a bow may work too with high INT or DEX respectively) will stun her instantly and as long as you are reasonably close the spider will nearly always start its lava spew attack providing you with a long window to attack. Quelaag will then wake up and can be stunned again (note if attacking in melee Quelaag will usually use a flame aura attack as she wakes).
Stealth and Diversion
Summoning Maneater Mildred and letting her draw aggro away from you makes for an easier fight. You must still be careful in melee as Quelaag will often switch targets but ranged builds can easily run away until she switches back to Mildred.
(Requires online phantom/s)It is possible to stunlock Quelaag with the Gargoyle's Halberd or Great Scythe. You need to two-hand the weapon and time your R-1 so that she is locked in place and cannot cast spells. You will want to go up in front of her and attack her human torso. Attacking Quelaag's human body also deals extra damage. While she is stunlocked have your phantoms just attack her nonstop until she dies. Very simple method as long as you have enough stamina regen.