Lukas Fellner

While searching the sewers for a pair of magical daggers desired by Nordbert Cotton and the Baron who he serves, The Party came across a small makeshift cell, where they found inside an emaciated and dirty man who introduced himself as Lukas.
He explained that he had locked himself in there almost a year prior, after having found himself to be cursed in some way. This first came to light during an orc raid on a Berstock Tree where he was working as a miner. He explained that as the orcs approached, he fainted, and when he returned to consciousness everyone except him and his close friend were killed, including all the orcs. His clothes were torn and he was covered in blood.
He became haunted by violent dreams where he would be tearing people and animals apart with his bare hands, and he was fearful that these were not dreams at all.
He started to be approached by The Baron's Men, who were keen to recruit him into their organisation - Lukas never gave them the chance to do so and would always run from them.
The Party freed him from his makeshift sewer cell, and promised that they may be able to help him. In doing so, they noticed that his bars were made of silver. He became frightened and agitated as the party began to press him on the nature of his curse. Testing a theory, Gromp-Ghar threw a silver coin at him, which he instinctively caught.
The coin burned his hands, and the cornered man revealed his cursed form - he was a werewolf.
Before they could talk or learn more, he ran from the sewer.
On learning of his escape, Nordbert Cotton tasked Gromp-Ghar to capture him and return him to the Baron. To help in this, he provided the half-orc with a silver chain.
The Party tracked him down, initially visiting Stella Bauer who pointed them to a Jeweller, Ingolf, in the Middle tier who had sold silver to a man named Melvin. They then tracked Melvin down who ultimately, under duress, agreed to take them to the tree where Lukas' curse first revealed itself. 
On the way, they encountered several unusually aggressive animals, but managed to fight their way through to the tree where Lukas' was in his werewolf form. After a long fight they managed to weaken him enough to subdue him and wrap him in silver chains.
After an argument with Melvin about where to bring him, they took him to Nordbert Cotton, as agreed. Melvin, desparate to support his friend, dutifully followed. As the entrance to the thieves guild opened, magical energy emerged from it and the restrained werewolf floated down into the hole.