Voids Appear as a big pink oval looking hole. They spawn randomly inside of all spawns and I believe at this time there is two different locations in each spawn of which they can appear.
For the voids you need a minimum of 4 voids in total, and i recomend 1400 void points before you go into the void room. The void room is located inside the TP room to the south down the stairs.
Once you have your minimum kills and points click on the big gold circle world looking thing.
take a team of 2+ players and clear out the entire room.
WARNING- Once you enter you lose your voids completed and your points
Once completed You will receive a cursed charm, You can only use one of these charms at any time however you can hold more in your BP and swap as needed. In addition if you dont like your charm and you have completed 4 more voids, you can sacrifice your charm on the coal basin to the > of the void realm room.
It will give you 100-400 void points of which i am unsure of the amount.