Each of the maps added by the Back to Ubersreik DLC has a puzzle which the players must solve, to acquire a hidden dwarfen rune (and indeed these runes are the entire plot reason for the DLC occurring in the first place). Once these runes are acquired, they are carved into the Dwarfen Lodestone in the keep by Olesya. After all three are acquired, the player can interact with the lodestone to launch the hidden map, Fortunes of War. Note that the runes do not need to be transcribed by each player individually, as long as one player completes the puzzle and transcribes the rune, all players in the team will be granted the rune in their respective keeps upon completing the map. Runes can be gathered on any difficulty, and once Fortunes of War is unlocked it can be launched on any difficulty, so there is no requirement to do any of this on higher difficulties. All of the puzzles can, in theory, be completed by a single player, although several of them will be much easier with a team as they require carrying items through long stretches of the map, so having other players willing to cover the carrier will significantly speed things up.
The rune itself is located in a chamber late in the level, after the player leave the Jungfreud Platz, on the stairs up towards the inn. Looking through a gate here, 10 candles are visible, 5 of them lit. From left to right, the lit candles are the 2nd, 4th, 5th, 7th and 10th. This is a clue to the puzzle players must solve throughout the level.
There are 10 "suspicious bricks" which have been added to the level. Players must press the 5 bricks corresponding to the lit candles, by order they are found in the level. Pressing a single incorrect brick at any time will void the puzzle and require a new run of the level to complete. To simplify things, none of the incorrect bricks will be listed here, so DO NOT ALLOW ANY MEMBER OF YOUR TEAM TO PRESS ANY BRICK NOT LISTED HERE.
The first brick you need is located early on, before entering the garrison. Instead of heading up the stairs, turn right and look for a suspicious brick hidden behind a crate against the wall to your right.
After heading through the pig pens, you will reach a small bridge, then a gate into the next street with a wagon alongside it. The brick you need is hidden behind the crates to the left of the wagon, if you are facing the gate. You may have to jump on top of the crates to reach it.
Instead of heading through the gate, turn right, into the back alleys. Turn left and follow the alleys until you find a cellar door. Head down into the cellar, and turn right into a small, semi-hidden alcove. The next brick is located at floor level in the back here (this is where a book was located in Vermintide 1).
Once you reach the Jungfreud Platz, turn left and jump onto some raised crates, then across a wooden beam and onto a nearby roof. Jump around the corner, then carefully drop down from this stone platform onto a small stone ledge, with a tome. Behind the tome is the brick you need.
The final brick you need is hidden in the inn after the Jungfreud Platz, just after passing up the stairs past the rune chamber. Once you enter the inn, look for the brick on a pillar behind the bar.
Once all five bricks have been pressed (and NO others), you will hear a message from Olesya, telling the players that something has changed. Head back out of the inn and down the stairs, turning right after going down a level, then head into the now-unlocked rune chamber at the end. Transcribe the rune by interacting with it, then finish the map as normal to unlock the rune in the keep.
Once the players reach the main open graveyard area (after receiving the "Find the source of the green poison" objective), clear this section of enemies. Look at the crypts on the left, and locate a pedestal with a stone skull on top of it. You should be prompted to interact with this skull (although it will NOT receive the white outline that other interactable objects normally get). You will get a message from Olesya once you interact with it, telling you that you're on the right track.
This next section does have a time limit, although it is quite lenient. You must find and light four candles in the immediate area, to open the door to the crypt. If you fail to light all four in time, the candles will blow out and you will have to start again.
To find the first candle, head behind the crypt with the skull, and turn left. The candle is in a small courtyard here, on top of a headstone.
Head to the back wall and jump over it. Just past here on your right should be another candle on top of a headstone.
Use the nearby cart to jump over the graveyard fence. Head towards the pillar in front of you, the candle should be located on the edge of it.
Head back into the main open graveyard area. Run toward the back, nearby but just past the crypt, and find another pillar. The final candle is located on the back side of this pillar.
Once all the candles are lit, the crypt will open, and reveal an empty tomb with a broken gargoyle head inside. Now comes the carrying section. This gargoyle head must be carried through almost the entire level, until just before the final cauldron event. It does not matter who carries the gargoyle head, it does not need to be a single player the whole way, and it can safely be dropped in order to fight hordes, specials or bosses. However, do not lose the head, or lose track of where it has been thrown, so it is preferable for one player to focus on keeping track of the head.
Play through the level as usual at least until reaching the stairs up towards the final cauldron event, but do not drop down into the poisoned cauldron room. In the level before the final stairs up to the event drop, look around and find a series of windows on your right. Drop down here onto a stone platform, and at the end will be a headless gargoyle (whose missing head will be highlighted if someone is carrying the gargoyle head). Throw the head into place, and you will again receive a message from Olesya. Turn back around and drop down off this ledge to a lower level, and the rune chamber will have opened behind you. Transcribe the rune, head back up the ladder, finish the cauldron event and complete the map to receive the rune in your keep.
This rune puzzle requires at least one section to be done by the host, so make sure the host knows this.
After entering the first cave section, keep to the left, to find a semi-hidden passage that leads out to an open area with a chest. Turn around, jump up the rocks at the end of the area, to reach a hidden area above the doorway you came in through, and find a torch. Olesya will comment at this point. Pick up the torch, and carry it through the level.
You will not have to carry this one as far as the gargoyle head. Once you reach the bridge over the canyon, head up through the forest until you come to the log you have to pass through. Instead of going through, turn right. There will be a felled log here, jump on top of it, then hop over onto the war banner. From here, hop to the left onto a ledge and follow it around into the tower (this is also the path to the grimoire).
Inside the tower is a fireplace. The host must take the torch, and throw it into the fireplace (by dropping it, i.e. switching weapons with it equipped). This will illuminate the room. Opposite the fireplace is a table with three models on it. Take note of the models and remember the order in which they appear, left to right. This is the solution to the next part of the puzzle and is random each run. Take a screenshot if you need to, but try not to block the light, so the models are visible.
Play through the Doomwheel event as usual, and out through the courtyards, until you are about to leave the courtyard area and head down toward the river. Just before the final archway out of the courtyard, turn back, and look for vines growing out of the wall. Leap onto these vines, follow the across and then hop over a couple of ledges to an upper level (this is also the path to the last tome). At the end here will be 5 statues, 3 of which match the models on the table you saw earlier. Interact with the skulls on the bases of these statues one by one, according to the order of the models on the table earlier. Once you interact with the third, Olesya will react, and the stone wall next to the tome will open (note that there is a bug here, Olesya may play a voice line stating that your answer was wrong, as long as the wall opens just ignore her). The rune chamber is just inside, and again simply transcribe the rune, then head back out and finish the level as normal to retrieve the rune for your keep.