Here's the fight with the darkbeast. Again, fuck this boss and fuck From Software for even thinking it up:
https://www.youtube.com/watch?v=oaWfMud5ewM
#neveragain
And here's the other defiled Amygdala with the same character:
https://www.youtube.com/watch?v=f1TMGw6U5U0
For those still stuck with it, just follow these steps:
For the first two phases, keep its head locked and stay at a safe distance in front of it. Bait its arms by approaching and retreating with quick steps. With a short-range weapon like the cleaver, you'll need the transformed mode to actually land some hits. Don't exceed 3 in the first phase, and don't go over 2 in the second phase when its hands glow have a small aoe around them. You'll also want to delay your sprinting in the second phase because charging at it as soon as the hands slam the floor will throw you back.
Ignore swiping animations like the one during 1:28 and wait for it to do something else. Same for the lasers. You can bait a second attack during the animation at 1:58 if you approach, retreat, and go back for the hits. It's not necessary, though.
In the animation starting around 0:44 of the video, you can get 3 free hits by sprinting towards it. It also does it in the second phase around 2:58 and even 3:21.
Phase 3 starts at 5:08. Self-explanatory. Stay at the crotch, at a safe distance from the stomping feet, and wait for it to jump. RUN towards the crotch (or where it was) and get your hits in or a charged attack. By the third phase using the strategy, you pretty much won already.
I definitely think doing ABSOLUTELY NOTHING while it jumps is not always safe, regardless of where you're standing. Standing by its tail will only make Amygdala spin and track you, making it easier for you to get stomped or jumped on. Just do what I do, simple.