Originally Posted by
Amphion
The achievement is not really clear on what you have to do.
You have to have 8 inside one whirlwind. the best way to do this is start the boss on the the opposite side from the door, when he spins the first time you drag the adds down to the middle on the oppsite stair hes taking up. 2 adds spawn as hes spinning around. you will loose these 2.
When hes done spinning, you can run to the door, and wait there until hes spinning the next time, you should have 8 adds alive by now.
wait for him to get closer. and then jump into the pit, so he can soak up all the adds, and you kill the boss.
You have to be alive to get the achievement.