Clotho
The final Sister of Fate isn't just a nasty boss - she's an entire level unto herself. Start by sprinting past the swinging blades and into the first area. You'll see two areas, to your right and left, containing broken stairs and chubby little arms sprouting out. First, head left. Batter the arm until it limps down, and then use the lever to open the grill above your head. Run back to the stairs, jump off and glide, and you'll make it to the chamber with the chest in it. Open it up, then climb the wall and work your way around to the right hand side, where you'll see a few corpses blocking the grill. Clear them away, drop down and repeat the process with the lever. You can now rope up and head up to the next part of the level.
When you emerge, you're greeted with a complex-looking puzzle. Don't worry. Run left (avoiding the arms) until you reach the lever that opens the trap door. Pull it, then bash the nearest arm until it dangles down into the trap. Shut the trap. Now move to the next arm, which should be by a raised platform with a lever on it. Batter the arm, climb the rope, activate the lever. Now go back to where you disabled the first arm, and start to drag the device along the side. When you reach the slot before the final arm, leave it there, cripple the arm, then quickly drag it past until you get to the final slot. You'll see a brief cutscene. Drag the device back a notch and batter the final arm until it gets speared. You can now climb the rope into the top level of the Loom Chamber.
You should now be looking the hideous third sister, Clotho, in the eye. Slow down time and batter both her arms until they're useless. Activate the two levels by the edge of the arena, and it'll bring up a couple of corpses. Head to the right hand side and climb the wall by the door, until you spot another couple of corpses hanging on the railing. Clear them, then drop down and hack at Fate's arms again. Now move the level across the edge of the platform until it lines up with the chain in the middle. Yank up the blade. Fate will probably gain use of her arms again, so return to them and make them limp once more. Now return to the blade, rotate it to face the creature, then get behind it and pull it back. Let go, and you'll enter a Quicktime sequence, where you ram the blade through her head.
