Duach, at the North end of the mine, is of little interest- he’s a Forsworn who’s been here for some time, but he doesn’t really have anything to say. Similarly, Braig at the far end has nothing to say, but he’s a bit odder about it and kind of threatening. More interestingly are Odavan and Grisvar. The two are not related, but they are usually found standing together. Odavan has only joined the Forsworn since he’s been in the mine, as that makes things easier on him. Grisvar, on the other hand, is the one to go to if you want a shiv. He’s willing to provide you with one, but first he wants some Skooma- and according to him, Duach has some right now.
After agreeing to Grisvar’s request, you can head up to Duach and talk to him about the skooma. When you mention it, he threatens you- but you can still try to get the goods off of him. You can choose to beg for it, claiming you need it badly and attempting a Persuade, or you can try to beat it out of him with your bare fists. The brawl is certainly more likely to work, but it takes a while, so if you’re pressed for time or just really good with Speechcraft, you may want to try Persuade anyways.
Either way, you’ve likely managed to convince Duach to give you the skooma, so take it right back to Grisvar and trade it for the shiv. If you like dual-weapons, then you can put a pickaxe in your off-hand, though it’s really not as effective a weapon as the shiv by a good ways.
Now that you’re equipped just in case, it’s time to go make your way to Madanach. Return to the main chamber of the mine and find Borkul the Beast. He calls you ‘new meat’, and asks you about your first kill- he’ll respond positively if you’re enthusiastic about it, or derisively otherwise, considering you mostly unimportant. He is, however, impressed with the Forsworn since his arrival in the mine twelve years ago on being caught by the guards. According to him, he’s in jail for murder, banditry, assault, theft, and (horror of horrors) ‘lollygagging’.
You have three real options for getting past Borkul- if you talk to him, you can get a chance to trade a shiv for permission to go see Madanach. This is a poor trade, leaving you without a good weapon, particularly when other options are available. For instance, you can convince Borkul to let you take him on in a fistfight for the right to see Madanach. This is a bit tough if you’re not heavily invested in Health, as Borkul hits hard and takes hits very well. Those of a more covert nature can stop talking to Borkul entirely and creep around behind him- a bit of luck with pickpocketing will let you swipe his key so you can open Madanach’s gate and get in to see the King in Rags. It is technically possible to convince Borkul to let you through by feigning some sort of an appointment with Madanach- but this requires a truly remarkable Speechcraft level. If you can pull it off, though, you have a no-risk entry, which is nice.