XLIV. Boss Battle - The Throne of Lahkesis (Sister of Fate)
This is a toughie. She'll come at you with spear attacks to start with, and some blasts from her staff. Alternate between slicing her with your blades and deflecting her blasts. Eventually, she'll start floating higher up, forcing you to change tactics.
She'll blast you with her staff, slam herself down, and electrify the floor. To avoid all these, you need to keep jumping, and when she takes the floor out of action, use your grapple to swing above it. She'll fire at you in mid-air too, so keep moving between grapples to avoid her shots. The best way to bring her down is with your bow, and by deflecting her shots.
Finally, she'll hang in midair - ready for a beating. Grapple up and swing into her while pressing Circle and you'll get the Quicktime event to finish her off.
XLV. Boss Battle - Atropos
Don't worry, this one is much easier. Use Cyclone of Chaos on the grunts that appear, and whenever you get time, fire arrows at the Sister. Repeat until she slumps onto the sword - letting you finish her with a Quicktime sequence.
XLVI. Boss Battle - The Two Sisters of Fate
This fight is the same as before, only with a twist. Atropos appears to have a pop at you every few seconds, so you need to be quicker on the dodge. Lahkesis is your primary target, so focus your attention on her. Once she goes down, freeze time, and smashes the mirror with the second sister in it. Once you've broken the two at the side, hack away some more and you'll finally get a Quicktime to finish them both.
