The void keep is only open on Sundays and is necessary for ascending void champions. The boss itself is pretty straightforward, he just throws out poisons which can't be resisted. Block debuffs buff can work here but his minions throw out a block buff debuff which can make it hard to actually use on auto.
The main key here is bring damage dealers, speed and a cleanser. As always, someone with atk up on allies and def down on enemies will not only increase your speed but success rate.
![](https://i.ytimg.com/vi/oM-QZuc4gIk/maxresdefault.jpg)