AonEne

OH and White Defender, I only tried the second version once but that double damage  

I can't do path of pain because my keybinds are bad for it (and bad in general but they're what I use for everything else), but I've done the rest. 

With a lot of them you just gotta fight em a lot, unfortunately. If I were to watch you do them, I could probably tell you where to improve. Trial of the Fool is really hard no matter what you do, unfortunately, but the rest are pretty easy when you know what to do.

My boy Grimm is probably the easiest of all of them. He only does like five moves and once you (like I have) have beaten Nightmare King Grimm a dozen times, you get these movies pretty down. There's like one response you need for each move, and you just gotta repeat those over and over and hit him as much as you can while playing safely. 

Failed Champion's biggest challenge is the issue of double damage and the falling rocks. To tell it true, I still don't know how to dodge those things, I just don't get hit by them much anymore. You have to not be too aggressive with Failed Champion, you should stay fairly far from him and not move except when he's coming for you and use those opportunities to hit him. If you use the dream nail during his stagger and hit him after each heal, you can heal back to full and then get full soul. If you have full soul, you can stagger him again without him doing more than one move, then get full soul again to stagger him. Rinse and repeat until he's dead.

Soul Tyrant is honestly not too hard, I think. The hardest thing about him is that the battle goes on for absolutely forever and you have to focus the whole time. The spinning balls move where he moves from one side of the arena to the other is the hardest to dodge, but you can walk to the farthest part of the arena and stand against the wall, then jump when one of the balls comes for you. Everything else is the same as the first soul guy.

Grey Prince Zote is the worst.

With White Defender, you should stay near him and attack whenever he's in range. Use Howling Wraiths when he hops out of the ground to spit dung everywhere. He's not much to deal with as long as you're not being too aggressive.

I hope all of that's helpful, I can showcase other stuff if you want any more.

Thanks for the advice, I'll try to keep it in mind!