D3 Achievements Guides: “Challenges: Act I” or “A Brief Butchering”
Kill the Butcher in under 2 minutes on Inferno difficulty.
This achievement is more of a gear check than anything else, although you can bypass it with help from your better geared friends. Remember though, all enemies gain additional health as you add more players to the game, so unless you know they have decent DPS, adding additional players may actually work against you.
First thing is first. You need gear to beat this fight in two minutes. The Butcher on Inferno is no joke.
The Butcher has a few abilities, and regardless of your class, if you can avoid all of them (aside from the melee swings – but that too only applies to melee classes), and thus maximize your DPS time, this achievement is actually a lot easier than you think. The Ancient Spear and Charge can both be side-stepped. The Massive swing has a massive tell animation, so you can avoid that as well. As melee, you need to be able to take the normal melee swings and the fan of knives attack. As ranged, you just need to be able to take the fan of knives every once in a while – it is harder to avoid because it is instantly cast.
The final problem, of course, are the floor fires. I would suggest that you stand on the boundary between several floor tiles to give you some good options.
One last tip: blow your cooldowns as he starts his Charge animations, and position yourself so you can maximize your DPS while he is incapacitated.