For some of the "Challenge" achievements, the specific challenge revolves around killing a boss without getting hit, or hit by specific attacks:
It occurs to me that loading up on dodge and/or block might save a boss run for this achievement if I get particularly lucky. I'm not sure if this counts, though. If the attack intersects my location, but I took no damage (ie, I dodged or blocked), does this count as getting hit?
How do abilities that absorb damage change things? Can I keep something like Diamond Skin on and "cheat" that way?