Valor Mortis is all about peppering the parkour and parrying action with questlines that showcase the bleakest and most depressing fates of those who called these lands home before the corruption.
You'll come across one such bleak quest when you explore the wooded area of Chapter Five. You'll come to a little house in the woods, and inside, you'll find a man hanging from a noose.
Your job is to try and make sense of why this man took his own life.
How To Get Inside

Before you can begin this quest, you'll need to find a way inside the home. To do this, head to the right-hand side of the house. As you do, you'll encounter a Howler enemy, so try to sneak up on it and take it out before it pounces on you.
Then, once you have dealt with the demon dog, look inside the window, where you'll find a weak spot in the corruption that can be shot to clear the way for you to open the front door.
Finding The Basement Key
As mentioned, inside you'll find a man hanging from a noose, and nearby you'll find some artwork.

It's easily missed, but you can interact with this painting, and this will give you a line of sight to yet another weak point. Shoot this, and you'll be able to head up the hill to the right of the house.
Once you do, you'll witness a flashback near the grave where the man and his wife grieve the loss of their child, and buried there is the Basement Key.

Head inside and use it, and this will grant you access to the lower level. Beware that there are a few projectile-spewing and Carrion enemies attached to the wall inside. Kill them, and then head to the area with all the poison apparatus. Here, you will witness another flashback, and the door nearby will swing open when it concludes.
Possible Bug: In one of my playthroughs, this quest bugged because I did not have access to the flashback, and the door forward didn't swing open as it should have. So, it could be worthwhile to make a cloud save state, just in case.

This leads you to the quest finale. The revelation that when the wife found out that the artist was in cahoots with the rebels, he killed her to keep her quiet, causing a madness that would have him take his own life.
Finding her will complete the quest, and you will receive the Amber 'Butcher's Carnage' for your efforts.