How to Defeat last bosses??

How to defeat last bosses??i beat the grand champion and finally meet the last boss atharasus)

http://www.hunterislandforum.com/index.php/topic/6493-atrahasis/#entry64903

My best tip is to have a monster with Unwanted Friend in the frontline. It’s incredibly helpful as it prevents him from summon anything. One with Purify in the frontline is also required to stop his Poison Massacre. After that you want as much single target damage as possible, such as Poison Eaters and Assisted damage dealers. In the backline you want as many monsters as possible with Hold Ground and Desperate Strike to counter his Desperate All and deal a ton of damage back. This makes it incredibly easy.

I should say this though: Purify and Unwanted Friend is the most essential part of this strategy.

Hmm…i should try it,but first i must hunt more monster,my team was not strong enough.thanks guys!