Sant V. Schreiber's Count Orlok

Old tales speak of a monster which terrorized almost the entirety of what's now known as Eastern Slovakia in the Middle Ages. Legends are told of a shape-shifting creature, capable of flight, which prowled the Moonless nights. They mention a tall, thin and bald figure, with pale skin and a large mouth full of sharp, blood-covered teeth, cloaked in a black cape, disappearing into a cloud of mist. The creature moved silently, leaving no footprints, nor making any noise, as it wasn't breathing at all. Its victims were found dead, drained of all blood, left in unnatural and twisted rigor mortis with broken, or sometimes completely smashed bones.
It is believed that one day, a mysterious man in a large leather coat and a hat came looking for the creature. He apparently managed to follow it and track it down to an abandoned castle. After not hearing from him for a while, he appeared in a nearby village one day.
"The caste ... stay away from it ... for all your sakes!" ... Those were his last words, before he succumbed to his gruesome injuries.
From that day forward, the creature vanished altogether and the attacks stopped. Did he defeat it? Or did he manage to lock it in its lair for good? This shall remain a mystery.
For now ...
A small group of friends, driven by blind courage, or perhaps sheer stupidity, visited the said castle afterwards, only to find nothing, but a ruin.
Upon further exploration, they came across an entrance into the dungeons underneath one of the guard towers. The doorway, inscribed with strange glyphs, was collapsed, blocked by huge stones and what used to be a ceiling of the hallway. As they looked closer, the light from their torches revealed a horrific sight. Human bodies were crushed in between the stones, serving as some kind of sick mortar analog. As they fled in terror, one of them tripped and broke his leg. His screams echoed through the empty castle halls and were the last thing his companions heard as they ran. Only a lit torch to keep his company, the poor fella spent his last moments at the bottom of the guard tower. Perhaps it was exhaustion of slowly approaching death, but he kept seeing something in the shadows. A strange mist, a silhouette of a man, dancing in the flickering light of his torch. Silent whispers coming through the stones from the dungeons below ...
Decades have passed.
Archeologists and historians were slowly showing interest in this castle's ruin, on a hill above the town of Košice. Over the years, the ground shifted and stone succumbed to the elements, revealing a part of the passage into underground dungeons. A terrible and chilling discovery was made ... the remains of at least a dozen different human bodies among the collapsed stones and an almost intact skeleton with nary one broken leg. Near it, an old torch, a piece of wood with a horrific depiction of what looked like some humanoid monster burned into it and two words written with charcoal and ashes on the wall - Count Orlok.