On the way to a mid size town at the exact moment of sunset, the characters notice a black tower peeking out of the trees. Wherever they see it by the time they reach it it will have dissappeared. If they decide to search they will find ruins overgrown with vegetation where they believed they saw the tower. No secret tunnels will be found or anything of that sort. Just boring ruins.
When they arrive at the town if they mention it to anybody a silence will fill everybody within hearing distance and will slowly travel outwards till everybody is looking at the characters is a sudden quiet.
When prompted, the citizens will do a sign of warding and leave to go to their houses. Arguments may break out among a few locals about what the characters really saw. Many will laugh in the characters face. A few may question the characters on exactly what and where they saw it and eventually the characters will get somebody to talk and they will hear the story.
Forty years ago there was a tower in the area where the characters saw it. In it lived a minor noble of sorts called Jolgeth that had aspirations of great magic. Problem was Jolgeth was pretty much an idiot with little patience. He thirsted for power and the respect that came with it but was untrustworthy and ignorant. At some point he bought a book of the black arts that told him a way to get the power he so much wanted. So following the instructions in the book he preceded with the plan.
Through the night some skilled people he hired went through the town kidnapping all the first born children that were under the age of five and brought them to the tower. That night, calling on the name of the Black One, he sacrificed each of the children one at a time in hopes of acquiring awesome power.
The kidnappings did not go unnoticed but the gathered search team was too late to do anything when they arrived at the tower. Jolgeth, drunk with the power of the ritual, went outside and confronted the mob and told them what he did and why. With the new powers he expected to have, he tried to destroy the townspeople but the powers utterly failed him and the townspeople captured him. They gathered their dead offspring and locked Jolgeth in the tower after a severe beating. They wanted him to feel the fear of his impending death as added punishment for his deeds.. They then proceeded to destroy the entire tower burying Jolgeth inside.
It is said that while the townspeople were working on taking down the tower Jolgeth made a last call to his Dark Lord and sacrificed himself to his power. The townspeople heard a threat by Jolgeth to return someday and complete his search for power by enslaving the town and making them his first worshippers.
It will be the 100 year anniversary of the towers ruin in 30 days. The sign of the tower being back makes them think that Jolgeth may actually be making good on his threat.
It is a very popular story told in the town and many places around. Many do not believe it at all since there is nobody alive that actually lived through it. Those that believe it entirely and very scared of the premise of the tower reappearing are affected. They slowly become rash and rude to others, even if they were good natured before. Slowly they will be corrupted by the fear. Everybody else is affected depending on the distance they are from the tower. The closer they are the faster they are corrupted. Even those that disbelieve are affected.
The tower only appears at the moment the sun touches the horizon till the last glint of the sun passes so it is only viewable for a few minutes. Each time it appears its corruption aura spreads around affecting those within a 25 mile radius. The closer the more power the aura holds. They don’t have to see the tower to be affected.
His plan is once much of the surrounding area has been corrupted he will appear an offer them peace at the price of enslavement. The Dark One has given him power of persuasion and few can resist his call. Once he enslaves the town he will continue to stretch his reach as far as he can.
1)Could actually be that a wealthy illusionist is taking advantage of the story and using his power to create the tower. Many people are packing up and moving away scared of what may happen. The land of those that move he picks up at a dirt cheap price. With all this new land and farms he purchases he plans on later bringing in some people to work it in hopes of making a nice profit and being just like the nobility living off other peoples work. In this case the aura is not real but the towers appearance still puts people on edge. He may even hire some people to cause some ‘mystic’ trouble around town to cause even more fear hoping people will move away.
2)Jolgeth really has returned and is this time backed by the Black One giving him certain power. Characters will have to enter the ethereal tower, risk being trapped, and defeat Jolgeth and whatever minions the Black One gave him.