Before you try to decide the "what", start by asking the "why".
Is this place just naturally dark and gloomy? Is it cursed? If so, who cursed it? When? Is there a way to break the curse? Is the land protecting something? What? Is the land angry about something? When was the last time this land was "normal"? When was the last time the sun shone here and the birds sang here? When was the last time people lived here in peace?
Well.... what happened to change all that? Start with the story and that'll help you narrow down the specific monsters you need to fill it.
And remember - no one and nothing ever exists in isolation. Ever location has a logical ecology, even scary haunted places. Whatever lives there has needs. How are those needs met? If it's a monster, what does it eat? If it's an evil necromancer, where does he get the corpses for his experiments? If it's a hag, whose children does she steal?
Or maybe the land was cursed by an ancient evil. Was this the site of an ancient battle between the gods? Maybe an evil god was defeated and imprisoned here. Could the party find it? What would happen if they released it (even if by accident)?
Don't try to see the complete puzzle first. Just gather up your pieces first, and let those pieces tell you what the final picture looks like.
I do like the oozes and slimes or stuff in the upper levels of the ruins... and down below... you have the rituals of the Yuan-ti with a Conan sized snake in the middle of it all? Elves corrupted by magic who are led by a banshee? A shadow dragon that is collecting nefarious shadow creatures? And yes, a scarred beholder and it's children building a gate to another realm where they will draw support troops from to conquer this entire land? So many good options...
Before you try to decide the "what", start by asking the "why".
Is this place just naturally dark and gloomy? Is it cursed? If so, who cursed it? When? Is there a way to break the curse? Is the land protecting something? What? Is the land angry about something? When was the last time this land was "normal"? When was the last time the sun shone here and the birds sang here? When was the last time people lived here in peace?
Well.... what happened to change all that? Start with the story and that'll help you narrow down the specific monsters you need to fill it.
And remember - no one and nothing ever exists in isolation. Ever location has a logical ecology, even scary haunted places. Whatever lives there has needs. How are those needs met? If it's a monster, what does it eat? If it's an evil necromancer, where does he get the corpses for his experiments? If it's a hag, whose children does she steal?
Or maybe the land was cursed by an ancient evil. Was this the site of an ancient battle between the gods? Maybe an evil god was defeated and imprisoned here. Could the party find it? What would happen if they released it (even if by accident)?
Don't try to see the complete puzzle first. Just gather up your pieces first, and let those pieces tell you what the final picture looks like.
Anzio Faro. Protector Aasimar light cleric. Lvl 18.
Viktor Gavriil. White dragonborn grave cleric. Lvl 20.
Ikram Sahir ibn-Malik al-Sayyid Ra'ad. Brass dragonborn draconic sorcerer Lvl 9. Fire elemental devil.
Wrangler of cats.
This is some serious help, by knowing why its the ways I want it I kind of answer the what question. I'll keep this mindset going forward
I do like the oozes and slimes or stuff in the upper levels of the ruins... and down below... you have the rituals of the Yuan-ti with a Conan sized snake in the middle of it all? Elves corrupted by magic who are led by a banshee? A shadow dragon that is collecting nefarious shadow creatures? And yes, a scarred beholder and it's children building a gate to another realm where they will draw support troops from to conquer this entire land? So many good options...
Nothics always play really well with their Weird Insight