How do you kill the Demon of Hatred boss in Sekiro: Shadows Die Twice? This is an optional boss battle, and maybe the toughest in the game. It comes very late in the game, after the Fountainhead Palace area. You find this boss in the Ashina Outskirts area after backtracking to the Outskirts Wall Sculptor's Idol.
Sekiro: Shadows Die Twice - How to kill Demon of Hatred
This one is a doozy. Three health bars makes this one of the longest fights in the game, and his fire attacks (as well as the fire surrounding the arena) means you need to watch out for Burn damage on top of everything else. It goes without saying that you should bring with you as many items that combat the Burn effect as possible.
He has a lot of ranged attacks, so your best bet is to try and stick close to him as much as you can. Staying nearby, you can avoid the majority of his moves, although you'll need to be wary of his body slam. In this case, you'll want to get away ASAP. You can grapple hook back to him after the move is done to quickly close distance and get a few hits in on your way down.
You can block all his attacks aside from the fire-based ones, so remember to do so as well as dodging and jumping. You'll more than likely reduce his health before his posture, so just focus on getting some quick jabs in here and there to whittle him down and remove a health bar.
After performing the first Death Blow, keep your distance as he curls up and explodes. Once he does, the fight will play out the same as the first phase, so keep hacking away at his legs and staying close for the most part.
In his third life, the Demon of Hatred has a few new attacks you need to watch out for, most of them unblockable. He'll be able to put a ring of fire around the arena, reducing the size of the field, and many of his perilous attacks have extra hits in them. Once again, sticking close to him is key to success, circling around to avoid most of his attacks and backing off when needs be. Good luck, shinobi.
When you do finally take him down, you'll receive the Hatred Demon Memory, two Lapis Lazuli upgrade material, and a whopping 15,000 XP.