Notes from author
Start as a pyromancer, and as soon as you can get the Gold-Hemmed Black Set and Butcher Knife. Equip Ring of Favor and Protection and Dark Wood Grain Ring, and level endurance until you can ninja flip. Join the Chaos Servant covenant and equip any chaos spells you want.
I stumbled across this trying to find a strength build that I liked (I'd always done dex or faith builds before). I love the move set for the butcher knife; it's extremely versatile and has A strength scaling at +15. I started as a pyromancer just for the early-game leveling advantage, but I love the armor set, and the lore around the Witch and her daughters. Having the armor with the Mask of the Mother looks really badass.
You don't even have to level vitality, strength, and endurance to 40 for this to be a supremely OP PvE build, and the butcher knife's 2H strong attack's pinning move is great for PVP if you're quick enough. If you want to go further with magic, there is plenty of room to add more attunement slots, or some basic miracles or sorceries. To complete the pyro theme, buff the butcher knife with charcoal pine resin.