Demon of Hatred. Deflects ONLY. I'm proving a point.
If you didn't catch it, you can't break his posture with a deflection, so I jump on him to accomplish that because it felt more in the spirit of the challenge. Yes using the umbrella counts as deflecting. No I will not be doing this charmless or with demon bell, because I like myself. Also because it might be impossible with the buffed enemy posture recovery.
Do I recommend fighting him this way? No, there's a lot of downtime where you're better off getting some hits in, chipping down his health makes your posture damage stick a lot better.
But the point I'm making is that Demon of Hatred is emphatically not a Dark Souls boss. The game he belongs in and is designed for is the game he's actually in. You can deflect nearly every move that isn't a perilous sweep (yes, even the fire ones!), most of those with your sword, and the rest with the umbrella tool. Dodging around him for the entire fight is inefficient because it sacrifices posture damage; and in my opinion it's also just not nearly as fun as standing your ground in the face of a three story tall fiery monster.
And here's an 8 minute video to prove it. Thank you for your time.