The Dancer of the Frigid Valley is not a particularly hard boss in Dark Souls 3, given some patience and practice. Located at the bottom of the High Wall of Lothric, she has fanstastic music, stunning visual effects and an extremely unique moveset that will catch even seasoned Dark Souls vets off guard. The key to this fight, if you are a melee type build, is to stay close to her right leg but not so close that you can’t move backwards when she tries to grab you or does an AoE. You can recognize the grab attack by the sound played just before, while she simultaneously dips her shoulders. Every other AoE is done when she plunges her sword or fist into the ground. If you ever see her doing either of those move backwards. A good shield is extremely useful in this fight. One with high physical damage resistance, fire resistance and stability is preferred. Although you can block many of the Dancers attacks, it is recommended that you learn to dodge left or right (rolling if needed) as to conserve Stamina.
When her health reaches 50% she will reach into the ground and pull a second sword out. At this point, you need to back as far away as you can as she will begin to spin wildly with both swords for about 10 seconds. If you can roll through her last spin, you will be setup nicely for a few attacks. A few things to note about this fight: 1) The hit boxes or design of the Dancer make it so that you will often miss, even when standing right next to her. Try not to let this frustrate you and keep on with the strategy. 2) If you get caught early on in a combo, it is likely you will be hit several times before being able to get away, and it could likely end in your premature demise. Be sure to block at least the first hit and then try to roll through subsequent ones if you can, don’t do it the other way around.
3) She may do her spinning wildly attack a second time. Keep a sharp eye out for it and back as far away as you can. 4) The camera angle CAN get you killed in this fight. Try to stay in the center of the room if possible, only using the corners in an emergency. 5) Be careful when you heal. The boss sometimes will leap into the air and come down on you when you try. Make sure you have a good opening before healing and make sure you are out of reach of even her longest melee attack. Lastly, and I can’t stress this enough, Stamina management is the difference between living and dying. You cannot block all of her attacks and expect to attack afterwards. You must learn how and when to roll so as to conserve enough Stamina to still get 1 or 2 attacks in after her combos. .
As found on Youtube