How to Beat Pieta
Details
Location: Abandoned Redcopse
Resists: Holy, Physical, Smite
Weakness: Fire
Summons: The Iron Wayfarer
Rewards
Remembrance of Pieta, She of Blessed Renewal
1 Vestige Seed
10 Umbral Scouring
How to Beat
The best way to beat Pieta, She of Blessed Renewal is to bait out a very specific and easy to punish attack.
In both phases, Pieta uses the same kind of melee combo, and it is quite easy to avoid. She will attack from the left, then the right, then perform a third slash before slamming her sword down in front of her. Dodge into each attack, and on the final one, be sure to strafe around to end up at her back.
You can likely get a hit in no matter what, but if her sword glows gold while it is on the floor, she will remain there for a couple of seconds longer to create a small explosion there. You can continue hitting her in this time for a great damage window.
Pieta's other attacks don't leave much opportunity for retaliation, since most of them involve her making a fair bit of distance before using a ranged attack.
It is possible to break Pieta's stance by performing regular heavy attacks, allowing for a critical strike. However, since this is the first boss you will be dealing with, it is unlikely that your weapons will deal enough posture damage to allow this more than once at most before killing Pieta anyway.
The main thing to remember is that, since you don't have access to much yet, you should play conservatively. That will allow you to choose the right moments and bait out the right attacks.
Movepool
Sword Slash Combo: Pieta will attack with melee combos of up to four attacks. These are easiest to dodge when you are close to her, and have exceptionally long range. Always dodge forwards into the attack to avoid each swing.
Sword Slam: If you are nearby at the end of her melee combo, she may follow up with a sword slam on the ground. If she holds in position there with the impact area glowing, it will blow up after a short delay. You can avoid this attack by dodging the initial hit and then getting behind Pieta to get some damage in.
Light Beam: Usually used if you are far away. Pieta may raise her sword with a glow before lowing it down, aiming at you. As soon as the sword starts to lower, dodge to avoid the light beam attack coming your way.
Ground Attack: Pieta will create a patch of light on the ground that will rapidly track you to deal high damage. You can avoid this best by dodging forwards through it, as it cannot turn around on itself.
Summon Shade: Pieta will periodically summon up to two copies of herself to perform an attack, sometimes in tandem with a follow up attack from Pieta herself. These shade attacks can be melee combos, slams, light beams and ground attacks, all of which are avoided in exactly the same way.
Summon Flying Shade: Pieta will back away to one end of the arena before summoning two copies of herself. Each of these will position themselves on the left, right, or middle strip of the arena, if you are looking down it lengthways. They will then fly very quickly down the length of the arena, dealing high damage if you are in their path, and leaving behind a trail of floating swords. These swords, after a delay, will then drop to the ground for massive damage. Simply stand in the strip of the arena that the shades do not cover; there will always be one safe strip.
Grab Attack: Pieta will raise her arm and fly towards you in an attempt to grab you for massive damage. Avoid this by dodging to the right at the last moment, and get some hits in to punish the attack.