D&D 5E Making technology eldritch

[TheIdeaOfGood]

Hey!
My current campaign is roughly based on Darkest Dungeon with the characters trying to bring back order to a lawless stretch of land devastated by the cosmic horrors the lord unleashed. In addition, there are also brigands terrorizing the few inhabitants of the land. The characters have just taken out the brigands' main stronghold, an old keep.
What they do not know is that the area has always been a nexus for otherworldly shenanigans and the keep was once built on top of a crashed spaceship.
I like my fantasy with a bit of sci-fi to it
Now, I want the alien tech to ooze the same otherworldly menace that has plagued the area, showcasing that the universe itself is hostile to demihuman life and minds. Any tips on how to make that happen?

 

[Shadowdweller]

My most recent campaign was a sort of post-apocalyptic magitech thing. The land was littered with a variety of old and malfunctioning machinery that affected the environment. Don't know if it's directly applicable but a sampling included:

• A device that pushed objects and creatures into another dimension
• A biotech "computer" that looked like coral and transformed those who used it into fish-people
• Malfunctioning weather-control devices
• Ruins guarded by a biomechanical monster (too powerful for the PCs to defeat, but not capable of instantly killing them if appropriate evasive measures were taken)
• The "invisible fire". Essentially radiaoactive areas that caused slow damage to PCs without them being initially aware of it.
• Magical or technical items that periodically attracted certain creatures
• A mysterious disease, curse, or other effect that slowly changed other creatures into humans or human-like beings
• Mysterious transdimensional creatures with inscrutable motives seeking to use the PCs for their own ends.
• "Agricultural" machines that resulted in giant plants and creatures

...and a whole bunch of world-changing stuff like airships, flying cities, alien armies, anti-alien KKK, space stations, etc, that probably aren't appropriate for your setting.

 

[Paul Farquhar]

There are the symbiotic magic items in Eberron.

 

[Coroc]

My most recent campaign was a sort of post-apocalyptic magitech thing. The land was littered with a variety of old and malfunctioning machinery that affected the environment. Don't know if it's directly applicable but a sampling included:

• A device that pushed objects and creatures into another dimension
• A biotech "computer" that looked like coral and transformed those who used it into fish-people
• Malfunctioning weather-control devices
• Ruins guarded by a biomechanical monster (too powerful for the PCs to defeat, but not capable of instantly killing them if appropriate evasive measures were taken)
• The "invisible fire". Essentially radiaoactive areas that caused slow damage to PCs without them being initially aware of it.
• Magical or technical items that periodically attracted certain creatures
• A mysterious disease, curse, or other effect that slowly changed other creatures into humans or human-like beings
• Mysterious transdimensional creatures with inscrutable motives seeking to use the PCs for their own ends.
• "Agricultural" machines that resulted in giant plants and creatures

...and a whole bunch of world-changing stuff like airships, flying cities, alien armies, anti-alien KKK, space stations, etc, that probably aren't appropriate for your setting.

Whew. your players are in for a masochistic trip, I guess they could easily end up as radioactive contaminated fishpeople, who get out of the rain, into the other dimension ...

 

[TheIdeaOfGood]

Radioactivity! Damn, why didn't I think of that?

 

[MarkB]

There are a couple of Doctor Who episodes which could adapt well to this, if you don't mind a little body-horror.

In The Empty Child / The Doctor Dances, a futuristic ambulance's medical nanotech is going around attempting to 'cure' people, but because it doesn't comprehend human biology, everyone it 'treats' comes back wrong, changed to match a flawed template of what a healthy person should be.

In Girl in the Fireplace, the repair mechanoids on a starship run out of spare parts to repair it. In crazed, zealous desperation, they begin using the crew as an alternative source of spare parts, extracting organs to serve in place of mechanical devices - eyes for security cameras, hearts as pumps or valves, etc.

 

[WayOfTheFourElements]

There is this device. It's a large one - about the size of a wardrobe - and it keeps thing insides of it cold. In order to power it, each week the user must sacrifice a virgin and cover the device in the virgin's blood. Sounds messy, but it keep the ice cream from melting. Totally worth it.

 

[Cap'n Kobold]

Hey!
My current campaign is roughly based on Darkest Dungeon with the characters trying to bring back order to a lawless stretch of land devastated by the comic horrors the lord unleashed.

In The Empty Child / The Doctor Dances, a futuristic ambulance's medical nanotech is going around attempting to 'cure' people, but because it doesn't comprehend human biology, everyone it 'treats' comes back wrong, changed to match a flawed template of what a healthy person should be.

That fits with the OP. The nanotech could be turning people into clowns.

In addition, there are also brigands terrorizing the few inhabitants of the land. The characters have just taken out the brigands' main stronghold, an old keep.
What they do not know is that the area has always been a nexus for otherworldly shenanigans and the keep was once built on top of a crashed spaceship.
I like my fantasy with a bit of sci-fi to it
Now, I want the alien tech to ooze the same otherworldly menace that has plagued the area, showcasing that the universe itself is hostile to demihuman life and minds. Any tips on how to make that happen?

Eberron symbionts have already been suggested, but taking a look at some of the Regional Effects and Madnesses of the Daelkyr could fit if you have Rising or Exploring.

 

[GlassJaw]

Check out Monte Cook's Chaositech and the more recent Arcana of the Ancients.

Exactly what you are looking for.

 

[jgsugden]

Essentially, think of any horror / action story set in the future and drop it in your game.

• Skynet / Ultron / Brainiac - A technological entity wishes to wipe out all biological life. It creates machines to do just that.... You can do the same with biological creatures, such as a Yellow Musk Creeper / Zombie scenario.
• Alien / 10,000 other infestation stories - Someone brings a quickly reproducing alien life form out and it begins to wipe out all the people.
• Dark Angel / Nakita / other enhancement stories - Someone is using advanced technology to enhance people and use those enhanced people to do their bidding.
• Arrogant Jerks - The folks with the advanced technology think they're better than everyone else and try to secretly guide the development of others.
• Portals - Your advanced people are on another plane and there are portals between the planes. PCs can venture into the Pittsburgh of Gamma World.
• PCs discover advanced technology, need to figure out how to make it work, get a power source, and then repair it - in order to stop one of the above threats.