Aetherium Crystals
After talking to Peck, you will need to collect three Aetherium crystals scattered around the map to power the portal. The crystals are inside the canisters that are buried in the ground around the map. You will need an Aethermeter and a shovel to find the canisters holding the Aetherium crystals.
The Aethermeter is literally right outside Peck’s room. Wait for Ravenov to tell you the passcode, then interact with the locked cabinet right outside Peck’s office to get the Aethermeter.
Afterward, run right outside to the Scorched Defense area via the left exit and enter the bunker right outside to acquire the shovel.
Aetherium Crystals Locations
We will only get two Aetherium crystal canisters in this step. The last canister requires the RAI K-84 wonder weapon. So, we will collect that one once we’ve built our RAI K-84. One of the two crystals in this step will help us acquire the ‘power cell,’ which is the last part for the RAI K-84 wonder weapon. More on that shortly.
Aetherium Crystal Canister 1
The first canister is found in the Open Lot right by the OPC. You must check outside in the ground by the Planning Offices window. The canister will be in the corner under the platform.
Before you dig out the canister, get the essence trap from the Data Center and trap one zombie at the end of the round. Do this step at the end of the round to make it easier for you.
After trapping the zombie, dig out the canister. It will instantly disappear with a number of the same canisters spawning around the lot, inside the planning offices, and the engineering area.
At first glance, all the canisters will look the same. But, the difference is that one of them will not have black smoke around the crystal inside. All of them will have black smoke, except one canister.
Look around at all the canisters until you find the one without the black smoke, and pick it up. That will be your first canister. Although the canisters spawn in the exact same locations, the one without the black smoke is always in a random location but, of course, in only one of these fixed locations.
If you collect the wrong canister, a number of Mimics will spawn.
Aetherium Crystal Canister 2
The second canister can be found in the Jungle Defense area next to the Military Command building. Go to the middle dirt pathway, and you will get a prompt to dig out the canister.
Once you dig out the canister, a yellow-colored force field will develop around you. You won’t be able to leave this area now.
A number of hellhounds will spawn. In addition to the hellhounds, two Russian Manglers will also spawn. And this is where you can obtain the last part for the RAI K-84, the power cell.
Naturally, the Russian Manglers spawn on Round 15+. This is an easy trick to get it early. The only pre-requisite is that you must have collected all the other parts before collecting this second canister. This was the reason we did the RAI K-84 part collection early on.
First, the Mangler will spawn. Prepare to shoot at his arm to get the power cell. If you don’t get it the first time, try it with the second Mangler. But, you should get it on your first try.
Now, continue to survive the rest of the attack from the hellhounds and the Mangler. Be very careful of the hellhounds, they try to dodge your shots, and they do a lot of damage. They also leave a pool of fire where they die, which also does serious damage. Make sure you kill them as soon as they spawn in.
After clearing the area, the yellow force field will disappear, and you will be able to collect the yellow canister.
RAI K-84 & Third Aetherium Crystal
Now that you have the power cell, you will be able to build the RAI K-84 wonder weapon and use that to collect the last Aetherium crystal. First, make your way to the Weapon Lab, and plug the uncharged power cell into the charger and play through two rounds for it to be charged.
Once the second round finishes, head back to the Weapon Lab, and you will see that the color of the power cell will change to yellow. You will also be able to collect it.
You can now build the RAI K-84 at the workbench where you collected the blueprint from.
Quick Tip: If you are on round 12-13, you will get an assault round. You always get a free scorestreak from the computer at the defense site. When you get to the assault round, get the free scorestreak and save it for the final boss. It will help you reduce his health bar to almost half.
Back to the final canister. It is right by the stairs leading up to the Data Center from the Field Hospital and Barracks area. Go to the farthest exit of the Field Hospital by the barrier window.
It’ll be right by the exit door. Before digging out the canister, use your RAI K-84’s alternate ammo type first to shoot the dig site and then dig it out so that the canister doesn’t teleport. Usually, if you dig it out, it will quickly teleport to some other location, such as inside the Barracks or in the Field Hospital. You will always be able to find it within the same area, though. The “energy mine” ammo type of the RAI K-84 slows the canister down, allowing you to pick it up.
