The An Unheard Farewell side mission in Valor Mortis requires that William investigate the disappearance of a party of soldiers. To accomplish this mission, you need to search for the Valley of Ashes, clear plague-infected elevators, and locate the sole survivor of the soldiers. The accomplishment of this quest grants you Sleight of Hand Amber and also the Aggressive Reconnaissance Achievement.
An Unheard Farewell Quest

To begin the side quest, “An Unheard Farewell,” in the area of Valor Mortis, fast travel to the Guidepost Lantern located in the Valley of Ashes. Move along the road until you see the wooden platform. On the right, jump from one side to another. Then, turn left when you land there, and keep walking. There is going to be a Risen Grenadier on your way, and you have to defeat him.

Then, after the battle with the Risen Grenadier, proceed moving until you come across a broken cage. Go inside the cage, and you will come across the Adjudant Sous-Officier. He will ask William to investigate the case of his missing comrades.
How to Find the Adjudant’s Missing Comrades

In order to learn what happened to the Adjudant’s soldiers, head to the Demolished Path Lantern in the Valley of Ashes and proceed on this road. After you come across the damaged bridge, follow the road below it instead of continuing forward. Go through the lower road to get to the Climb Lantern.
There, clean up the plague that is infecting the lift so that you are able to use it to ascend to the upper level. Upon your arrival there, William will be shown the dire fate of the majority of the Adjudant’s fellow soldiers. While it becomes quite obvious that these soldiers met a gruesome death, it is not yet the end of this quest. William still has to look for any possible survivors of the Adjudant’s party.
How to Find the Last Surviving Soldier

Having discovered what happened to the soldiers, go ahead on the same path and use the stairs to get to the wooden platform. There you will find a musketeer, and behind the musketeer, you will see another portion of the lift that is covered with plague.
In order to remove the plague from the lift, there are two red orbs located on each side of the lift that should be shot down. After getting rid of those two orbs, you will find a secret path that can be accessed with the lift, and that is where you will find the Scout Commander, who is the only survivor of the Adjudant’s group. Defeat him to complete your search for the missing soldiers.
Should You Tell the Truth or Lie to the Adjudant

Having spoken to the Scout Commander, you now need to speak with the Adjudant Sous-Officier again. This NPC is going to question you about the whereabouts of his missing men, and you are free to choose whether to reveal the whole truth to him.
No matter what you choose, the Adjudant remains convinced that his soldiers abandoned their position in order to follow their enemies quickly and bravely. The only item that is affected by your choice here is your end rewards.
- If you tell the truth, you will get the Epic Catalyst Clot after resting at a lantern and returning to the carriage. The Epic Catalyst Clot will add 700 Catalysts to your inventory.
- If you lie, you will get the Remnant’s Return instead after resting and exploring the cave near the Climb lantern. This item helps gather all your fallen catalysts upon death, regardless of where you respawn.
Depending on what reward you are looking for, you should pick either of them by telling the truth or lying. Along with this, both options will give you a common reward called the Sleight of Hand amber. Successfully completing the An Unheard Farewell quest will also provide the Aggressive Reconnaissance Achievement for you.
