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Effect: Each round, a different type of zombie will spawn
Mocha Maul augment equippedIf you're able, I recommend playing on Tier III Cursed to gain access to Tier IV Pack-a-Punch as you'll want your weapons as strong as possible for the relic trial.
You'll need to collect three items, two of which can only be obtained from secret rooms, accessed by ejecting out of Tyr's Head. These items are a Helmet, Mister Peeks, and a Handheld Radio. The helmet is located in the secret room with the dead crew members, and the Mister Peeks is located underneath Ava's bed in the Ava Jansen bedroom secret room (see below).
There is a chance you get sent to one of these secret rooms or just back to the map as normal, so there is a bit of RNG to this and you'll need to flip a round each time you exit Tyr's Head to be able to re-enter it.
The final item is the Handheld Radio, which you're going to need an ARC-XD scorestreak for. If you don't already have one, there is a guaranteed spawn for one on the boxes in the Eidskallen Square.
Head to the Core Foundry and shoot/melee the small vent open in the North-East corner of the room. Place down the ARC-XD and follow the path across the water and into the lab where you'll need to detonate the ARC-XD next to some barrels to blow open the door.
Head to the Pack-a-Punch machine, where now you'll be able to access the Group 935 Genetic Lab, and if you look through the window on the left-hand side upon entering you'll find numbers on the walls from 1-5, two of which will have a radioactive symbol underneath, map those numbers to their corresponding letter in the alphabet as follows:
Afterward, look around the lab for the two jars labeled with the two letters you have in your game, pick them up, and place them onto the machine just to the left of the window barrier to retrieve a purple serum, which you can interact with to pick up.
Place the serum on the claw on the table in the lab to melt it down into a Necrospike, then interact with the jail cell containing the Uranium Canister to begin lockpicking the cell with the Necrospike, which once completed will allow you to pick up the Handheld Radio on cell floor.
Finally to unlock the relic trial, the person playing as Richtofen, on Round 15 or higher, will have to use 
Melee Macchiato to punch a barrel in the
Core Foundry to open it. Afterward, hold interact on the barrel to begin digging to eventually reveal the Ritterkreuz awarded to Richtofen during WWII, which
once picked up will teleport you into the quest, showing you the truth of Richtofen's past.
During this quest, after the ghost of Von List disappears off the chair, interact with the chair to place down all the items you collected, and if done correctly, you'll hear Mister Peeks laugh and the relic trial portal will be available in the Dry Dock. This relic trial is: Zombies can only be damaged when the player is indoors.
The zombies in this trial will be Round 60 scaled zombies, so ensure you're very prepared before entering. I also recommended Kazimirs and a War Machine scorestreak for the HVT waves.