DOOM

You must choose cacodemon at loadout. Once you get a demon rune, hold LT and highlight an enemy and press RT you'll grab with your tongue and chew them up for an insta-kill. This is super easy and quick. Just the first time I was the cacodemon, I got 8 kills that way. The hardest part is obviously getting possession of the demon rune.

As of the 6.66 patch on 7/20/17, all DLC for the game is free. Along with the patch, multiplayer progression has changed.

The Cacodemon does not unlock until you reach level 36.

Make sure you select Cacodemon when the match starts.

It is possible to boost this along with every other MP achievement on Doom.

requirements: minimum of 4 players

once you are in the multiplayer menu, push and select Asia-Pacific. As of writing this the Asia-Pacific servers are D-E-A-D as a doornail. nobody is playing on any mode.

once everyone is ready, select FIND A MATCH and select either Team Play or Team Deathmatch. Team Play has a few modes that spawn no demon runes (I believe freeze tag and infernal run do not, message me if I am wrong or missing modes). Team Deathmatch always has demon runes appear.

I suggest using Team Play to boost demon kills for the simple reason the modes it offers will give you cues on where to meet up. Domination and Exodus have icons on your HUD everyone can meet up at.

The game should match 4 boosters within 30 seconds everyone is searching.

demon runes take 1:30-2:00 to spawn and only last for about a minute. to get the most out of each rune, have the team that gets killed meet up by the rune before it is collected then move onto your meet up spot (again, its easier to do this on Team Play modes)

if you're well organized, you can get up to 8 demon kills with 1 rune

the fastest way to get kills with the cacodemon is to hold down . A circle will begin to appear, and once it is completely full,, aim at an opponent and push for an instant kill.