Dungeons and Dragons ideas

[Mie]

Hey guys I am doing a rpg for my baby brother and his friends and I could use a good idea for a plot twist or just a cool plot progression to throw at them. I am drying up here and kinda have a block at the moment so any ideas will be great to have. They are all teenagers and are all about the fighting but I want something different than just a cool monster, something that will make them go "Oh shit" like they used to do. Here's the story so far..

They are all orphans who was found around the same time and grew up together as best friends. One is a sorceress in an all wizard school, another is in the militia and the third is a rogue. They started out by doing a job to gather a lost artifact from a thief who had stolen it from the mage school but on the way there they visited a giant ruin that is the ruin of a 10.000 year old city, the size of a country, that stems from the times where races lived in harmony, but an evil wizard tricked the gods and set them up against eachother and during the gods war, pulled them down to earth and messed up the entire city. Several gods died, legends says all (In reality just 3).

They were told by an old chemist that had studied the place that almost all who entered were never seen again and with special glasses they could see ghosts there. They also got a warning that anything in there that could be seen without the glasses were the dangerous ghosts and to beware of them.

They entered the city and got a horde of evil ghostly ghosts after them, but were saved by a blue man in white clothing. He helped them and in return they let him out of the city, forgetting the old mans warning. He turned out to be quite the charming politicians and have slowly begun to turn their chaotic evil nation into something more law-abiding and have gained quite the following. He is in reality an undead priest from the times of old who became corrupt after spending centuries in a dead city, painfully aware of his situation and is out to take full control over the world.

They also spoke to the wizard who they now know is the guy who tricked the god and unknowing to them has become a demi god who was inprisoned on another plane, wich happens to be in an old prison wich he has turned into his own little death maze. They Managed to unknowingly free him from his prison and he know seeks to go head to head to the undead priest.

Meanwhile paladins are searching the area to find a band of demons escaped from the underworld that is destroying weak points in the world where the fabric of magic are thinner and portals can be opened to the underworld, temples are build on them to protect them but the temples are slowly being sinked into the grounds by these demons. They also mannaged to actually kill 1 of the paladins coming to save one of the temples.

They also gained a power to search out champions who have special powers and each time they kill one they get a special power themselves, the story behind that is that gods cannot be completely destroyed and when they did, their powers was scattered around the world, slowly materiating into people that hold parts of that gods power, and by killing the other champions they gain their power, and a step closer to becoming gods themself.

Seems a bit messy when I write it but yeah thats basicly it xD