Something like:
- Defeat Slurgal without letting anyone die
- Defeat Xada after letting him transform
Blink and you missed it: kill a boss in under 20 seconds
I can't find any boss with low health enough to down within 20 seconds, unless if you also mean mini-bosses, however, I'm sure that coding this for mini-bosses would be a nightmare if not outright impossible.
Dance macabre
*Danse