Kachua is the second boss from Sin and Punishment: Successor of the Earth and a minor antagonist. She is apart of the Armed Volunteers and has inherited some of Brad's blood, giving her strange powers.
Little is known about Kachua's past or her life prior to the events of the first game. She is allies with Brad and has inherited some of his blood, just like Radan, who may have been an experiment of Brad's and Kachua's. During Radan's attack on Tokyo, Kachua waited atop a building, stating that she is the bait to catch Radan. During Saki Amamiya's battle with Radan, Kachua tries to stop him and fails. After Radan's death, Kachua decides to fight Saki.
Kachua will begin the battle by summoning the bodies of Armed Volunteers and tossing them Saki's way. This attack isn't difficult to avoid, just stay out of the way and shoot/slash the bodies if need be. She'll then cause a pillar to fall, which is not very difficult to avoid. She'll then summon more bodies, but only several and keep them rotating around her. They'll begin expanding and as they near you just slash them to avoid getting hurt. She'll continue throwing bodies in new patterns until she summons an airplane to crash into you, all of which is still very easy dodge. The camera will shift and Kachua will begin moaning and lashing out Saki physically; all you need to do is slash her once to activate a cut scene.
Kachua will then stumble back and fall off the building, which is quickly followed by tremors and the city falling to pieces. Tokyo becomes flooded with blood, and as Saki becomes submerged, Achi telephathically tells Saki to show her what he's made of. Saki and Kachua then emerge as massive ruffians; the real fight begins. The first stage of this boss features only two attacks, a wide swing melee that can be rolled through and an easy to dodge projectile. Just shoot and dodge until you defeat her. The second stage features Kachua hiding underneath the sea of blood. This part is pretty hard, Kachua now has high speed purple energy projectiles and create large tidal waves. You can dodge through these, however the timing is difficult. Shell aslo send thin vertical waves of water at you in barrages. This is your best time to attack; dodge the waves bullet-hell style and fire at the little green light peeking out of the blood. She can also attack you with large flying vortexes, but they're not too difficult to dodge if it's not coming at the same time as other attacks. Now we have her third form, where she'll reemerge and immediately start shooting more of the purple projectiles. She'll shoot 6 at a time now instead of 2 and she won't stop, so just dodge and shoot the whole time.