One of my players for a campaign starting soon wants to play her background as a Haunted One, and she liked the prompt that a monster killed a bunch of innocent people, but left her character alive for some unknown reason. While we were talking about it, she liked the idea that the monster was standing over her, cocked its head at her, and then walked away without harming her, leaving her character questioning if there was something evil about her nature or if there was some other reason. She decided to leave the choice of monster up to me so I could possibly work it into the campaign at some point, and we agreed that her character would only remember a few details because of the sheer trauma of the event.

Now for the question bit - I'm having trouble deciding on a monster! I was considering something that laid an egg, a parasite, or a psychic sliver in her character's mind that could be laying dormant for the years of her monk's training that would follow this event, only to be triggered by something that happens in the campaign. I was hoping to find a monster that would fit with something like that, but I haven't had much luck yet. I could create something, I'm sure, but I wanted to see if there were any other suggestions first. Thanks in advance!!!

You could consider a Nothic. They peer into your soul and see your depeest thoughts and memories. Perhaps it saw something there worth sparing, or some destiny that awaits them, or some spark of the divine or the defiled.

Slaad or Mind Flayers might leave an egg/tadpole in their victim. Or maybe a vampire contaminated their blood somehow and left them to live and slowly become a thrall? 

I would also add the ideas of some sort of hag (or perhaps even a fiend). I could see some of the hag types leaving a child alive but cursing them to create more distress/torment later in life. The hag might have performed some dark ritual that implanted the egg/parasite in the character, which will one day hatch and/or grow enough to butcher and scar a new community of people. 

For example: The hag plucked a fat earthworm from the ground and whispered dark magics to it. The hag places the enchanted worm in the character's ear, where the worm borrowed into the character's head. It has been dormant and slowly feeding off of latent psychic energies, but the worm has slowly been transforming into a psurlon. Once grown enough, the psurlon will breakfree and cause havok.

A fiendish creature could do similar to the above, although I'd view them being more likely to leave psychological trauma in the hopes of letting that emotional damage causing further pain and suffering on others. Letting evil beget evil, if you will. 

A Phthisic. It's a psionic creature that is created from someone's madness. It didn't attack because it recognized that the PC has the potential to grow a phthisic of their own, it just needs more time.

Quote from Javier_Phenergan >>

I would also add the ideas of some sort of hag (or perhaps even a fiend). I could see some of the hag types leaving a child alive but cursing them to create more distress/torment later in life. The hag might have performed some dark ritual that implanted the egg/parasite in the character, which will one day hatch and/or grow enough to butcher and scar a new community of people. 

For example: The hag plucked a fat earthworm from the ground and whispered dark magics to it. The hag places the enchanted worm in the character's ear, where the worm borrowed into the character's head. It has been dormant and slowly feeding off of latent psychic energies, but the worm has slowly been transforming into a psurlon. Once grown enough, the psurlon will breakfree and cause havok.

 

A fiendish creature could do similar to the above, although I'd view them being more likely to leave psychological trauma in the hopes of letting that emotional damage causing further pain and suffering on others. Letting evil beget evil, if you will. 

To add on to this, a Night Hag could come with the benefit of making them a recurring npc (or many npcs) using Change Shape form to try to subtly steer the player towards whatever evil destiny they have foreseen.

Quote from dwaller2014 >>

To add on to this, a Night Hag could come with the benefit of making them a recurring npc (or many npcs) using Change Shape form to try to subtly steer the player towards whatever evil destiny they have foreseen.

I was coming here to say a Hag as well (but I was thinking Green Hag) because of their love of loss. So it might not even have been the hag who killed the people - but it was the Hag who saw her - and spared her - because the Hag wanted to break the Monk's purity - and perhaps has marked the Monk and can now track them and keep messing with them. The Coven, perhaps, needs the Monk to reach a certain point in their life - to eventually capture - and channel the purity into some dark ritual.

Casually do a poll of the Players about the kinds of bogeyman they have of their own or are aware of -- urban legends, myths, folklore, whatever. The monster under the bed, the clost monster, things of that nature.

Use the stats for a Noting or a hag, but don't make them readily definable as such -- they are the thing that haunts them -- which inherently means it returns, it sits in the corner of their eye, it passess bythem and raises the hair on the back of their neck or gives them goosebumps along one arm from the touch that no armor stops...

haunted one is a *required* background for several of my campaigns, and then they get a regular one as well. The basis is that I have a demon based on Pennywise that I use in my games. I use this as a way to increase the spooky factor, to test the reins of madness, to act as a recurring motif for a character -- and all of them have different ones.

I tend to create custom stats, but a few things always remain true:

They will appear whenever the character is busy. They may just appear in a crowd at a distance while they are bargaining, or be a shadow in an alley half glimpsed out of the corner of their eye.  In combat, they may run a hand along their shield arm or the back of a leg or through their hair. They will once in a while invade their dreams, disrupting their rest. The more tired, fatigued, exhausted they are,the more likely they are to appear.

They will whisper sounds at them.  and, once in a great while, they will appear next to someone in sight that is important to the party's goals, and make suggestions of killing them, miming it, but not doing anything.

And if the campaign is a long one at least once they will actually kill a person -- but will not let their pet be blamed for it.

All of it means that there will come a time when they have to face it -- but that's a whole story in and of itself, and ultimately requires the character to come clean about the history and all that to others if they want help overcoming it.

Thank you for all of the ideas! I actually took a little bit of a different direction with this than I originally intended, a bit of a twist to subvert what the player might think about why she was left alive. I'm going to have the village have been attacked by gnolls with no general purpose other than gnolls being a roving band of murderous *****. But the young child that eventually becomes the monk had contracted a version of Sight Rot disease that turns the eyes red. The gnoll who stood over her didn't want to touch her for fear of contracting the disease, and so left her there. That's it. That's why she survived. She's been thinking her whole life that there must be some dark reason she was chosen, but really it was just that a germophobe gnoll didn't want to touch her. The monks healed her, but the irises of her eyes were stained blood red. She was in so much shock and so young that she doesn't remember the monks healing her eyes. It'll come up later when we find another village on another world that is experiencing an epidemic of this same disease, and she's the only one who's immune. So it'll turn into a positive for her character after thinking it was a negative all her life.

Possibly a little anticlimactic, but I think this particular player will enjoy the subverting of the expectations and turning a flaw into something that can make her a hero.

Although...I might add later that it turns out she was deliberately infected with the disease for some nefarious purpose. Maybe once the child was blind, a demon would be able to see through her eyes and eventually take control of her or something. Perhaps she still has that dark tether buried somewhere within her... Who knows!

It depends on the exact vibe you are going for. 

You can get an alien vibe with a few creatures including 

• Mind Flayer
• Eldritch Lich
• Red slaad

You can dial that up to the extreme for a love crafting vibe with things like 

• Star spawn 
• Vestiges 
• followers of the great old ones or beings like Hadar 

There are also creatures with more a magical persuasion

• night hag
• lich
• nothic
• Dendar the night serpent and Yuan-ti Nightmare Speaker
• ghost
• demons