Matriarch Celeste is a demented cult leader with a love for electricity. With this How-To guide you’ll be able to snuff out her spark.
Matriarch Celeste has two phases. In the first she will lunge at you and attack from high. She only requires two parries to stagger, so waiting on either the lunge or the rising attack is best. Parry these to stagger her and follow-up with pummeling attacks. She is weak to fire, nano, and poison, so weapons with those statuses will help if you press the attack and afflict her with them. Dance around the arena and watch out for any sparks on the floor: these will electrify you, and Matriarch Celeste will savage you while your stunned. Do note: she will sometimes fake her lunge attack, so if you are trying to block it pay close attention to her attack animation before trying to parry the blow.
The second phase is much like the first, but now Celeste is more mobile thanks to her robo-robe arms. She will start to gather electrical energy during this phase (she will start to glow blue with energy all around her). When she does so either dash attack her, or use your drone to stop her. If she manages to finish she will electrify the metallic grating on the floor, shrinking the amount of room you have to avoid her without taking electrical damage. Otherwise, her attack patterns largely mimic the first phase with easy to parry lunges and high striking attacks. She will have split her weapon into two, however, boosting her attack speed. If you were doing fine parrying her in the first phase then continue to do so here. Otherwise, evade her attacks at the last minute before dashing in for a couple attacks.
Once defeated you’ll be awarded her weapon – the Icon of the Spark – a deadly Double-Duty weapon that does electrical damage.