Demon of Hatred is hard. Not utter BS hard, but hard enough to annoy me. His charge attack is just nuts. There's almost no dodging it, so you've just gotta make sure your HP is always topped off at max, or else a single charge attack will kill you. I almost had him today. He just needed two more hits and he would have died. Sadly I gotta go to the gym and then to work. Oh well. Will beat him tomorrow.
He is the easiest of the end game bosses as long as you clear the terrain and no where you are baiting him while keeping him in the center. Just run into his left most of the time and be ready to jump left at any moment, turn up the sound and listen for the kanji as missing it on his skin was the big problem for me after the terrain. The malcontent ring also makes phase 3 a joke, not sure if it does anything but I also used Devine confetti in phase 2 and popped ATK suger in phase 3 with the ring.
Everything in the above reply is my opinion, from my own perspective and not representative of reality outside of my own head!
-Android user, please be gentle with critique on my spelling.