This battle is quite simple, like the Necromancer one.
The Emerald Golem will raise his fists and pound the ground in place. He will then move whichever fist you're closest to and attempt to crush you in three positions. He'll pound left against the wall, then a bit to the right and finally towards his core in the middle. You need to slip underneath his fist, slash at the core and get out quickly before he raises both fists at the same time and pounds the ground. As you slash the core, he will fire off a green orb at you that you can either dodge or slash away.
After you've slashed his core enough his face will open up revealing his weak spot and this is when you need to run to either side, jump into the airstream and fly up with your wingsuit and slash his face. Depending on how quickly you make it up to his face, you'll want to do 8-10 hits and then get out of the way before giant green spikes reappear on the platform and hurt you. The more you slash his core and face, he'll change the order in which he pounds his fists on the ground, so you'll need to be quick. Slash the core a few times, get out of the way, go back, slash a few times etc etc.. You'll have to do 4 or more times depending on how many hits you can register to his face each time you get up there.
Now you've destroyed the Golem body and the spirit that was controlling the body breaks free, you'll need to use your wingsuit to fly around and slash it or throw shurikens at it. There are refills floating so you won't run out during this phase. This is by far the easiest part because all the spirit does is float around, he doesn't hurt you unless you bump into it, so keep throwing shurikens and refilling them until he's dead.