Dahaka:

Run around in a circle avoiding his hands until you find a white crate with steps on it. There should be a dagger hole. Run up and hang on to it, then run to the next one and go over the wall. There is a platform which is above the giant and it will trigger a speed kill sequence. You must time it correctly. Repeat this process a second time and you will blind the giant. He will smash part of the arena which will make it more difficult to find the ledge you use to attack him. Run around in a circle until you eventually find it. Do a speed kill sequence. Then, take him out by slashing his legs which will trigger the final speed kill sequence. If timed correctly, you can defeat him.

Run around him a few times and you will find a set of brown wooden stairs. Go up the stairs. When you are on them, there will be a location where you can run up and stab your dagger. There will then be another dagger location on your right where you must run to. Then, run onto the wall where the giant opens it for you. There will be another dagger location. You must then run up again, and then on your left will be a platform where you will be able to jump onto the giant and stab him. Repeat this sequence and you will blind him. You can defeat him by cutting his legs when he is blind.