- Wichts. With the spreading of Waidwen's Legacy, more and more children are being born Hollowborn. In an effort to cure it, a method was developed to transplant an animal's soul in the infant. And it seemed to work for the most part, with many of the children managing to supplant to animal soul with their own consciousness. However, as they reach adolescence, they become feral killing machines. Many families hid their children away, forced to watch them devolve into mindless killers. That is if the Wichts didn't just murder their own families to escape. Even scarier is that they count as "vessels" - they essentially count as undead for the purposes of things like Priest abilities.
- Even returning the souls via a Hylea win counts as this. Sure, it's great to all those parents who finally have the children they wanted... except this has been going on over a decade. Imagine seeing your neighbors happy that their young children are finally moving and acting like children, while you've got a teenager with the mind and abilities of an infant. Sure, the kid will get better eventually, but those years won't come back — and you almost certainly won't live to see your child come of age mentally.
- When you're told you should head to a town called Gilded Vale, you'd think it would be a standard foresty starting town. Then you see the tree...
- Two of the four possibilities for the town's ultimate fate also qualify as this: either letting the town slowly die under the rule of its increasingly insane lord - "In the end, all would hang from the boughs of the village's trees, watching over the dead town with vacant eyes." - or overthrowing him only for him to come back from the dead and slaughter the town.
- Skaen. If his physical description doesn't send shivers down your spine, just wait until you stumble upon his temple near Dyrwood and discover the chilling scheme of his adepts to get revenge at a noble. Said scheme involves kidnapping a pregnant lady who was raped by her uncle, infusing her with the souls of people who sacrificed themselves to Skaen and whose wills remained intact in a pool of their own blood, and send the brainwashed young girl back to her uncle, with the intent of making her kill him, and the rest of her family, herself.
- If your Cruel reputation is high enough, you can choose to sacrifice one of your companions in exchange for a status buff in Skaen's Temple, dooming their soul to join a pool of revengeful spirits for all eternity. And if you decide to sacrifice Grieving Mother, you will be rewarded with some rather dark humor, since no one notices.
- Also, during Act III, his eagerness to destroy souls just to spite Woedica. That is, until you discover during Act IV that he is just as willing to let her succeed. Yeah, Skaen is one hell of a warped god.
- Being Awakened AND a Watcher can be considered this. You are constantly haunted by visions of your past lives, relive the most traumatic moments from said lives very vividly, and also have the ability to commune with the spirits of the deceased. Which usually consists of them sharing the experience of their violent, cruel, horrific deaths with you. No wonder poor Maerwald is completely insane by the time you meet him.
- The Eyeless from the White March Part II. These things are big. And I mean, fucking big. Maneha and Kana are the tallest characters in the game, and they barely reach an Eyeless's knees. The Eyeless are vessels (meaning they are, for the purpose of spells and classification, undead), and they are nearly unstoppable. Your first meeting of them will be seeing the Iron Flail Fort, which you may or may not have carved through get stomped like cavemen with sticks, before three of them turn their attention to you. They killed off all the dwarves in Durgan's Battery, murdering them all without remorse or hesitation. As Ondra will tell you, these things are practically unstoppable. They don't eat, they don't sleep, they don't tire, and they don't know mercy, only their purpose, which they will see done no matter what. If their purpose is to kill you, well...
- Ondra: "The Eyeless cannot be reasoned with or fled from. One day, not far from now, they would kill you and level the Dyrwood."
Nightmare Fuel / Pillars of Eternity