Oreyn has a few duties for you this go around. The first missions is on-the-books, but also on-the-sly, the second mission is completely on the up-and-up, but the third mission is completely off-the-books.
The Master's Son
Oreyn wants you to go find out what happened to Galtus Previa. He wandered into Nonwyll Cavern (it's a bit north of Chorrol, but an easy walk) and hasn't been heard from since. You're going to have some company on this one: Viranus Donton, the Guildmaster's son. Mom does not know about this and is not to find out. Oreyn thinks that the Guildmaster has been sheltering Viranus too much following the death of her other son, Vitellus. If Viranus doesn't get some field experience, he'll never be ready for the higher positions in the guild (in more practical terms, he can't take over the guild if he never learns how to be a good fighter).
Your job is to make sure Viranus succeeds (translated as "comes back alive"). This is actually somewhat easier than it sounds because Viranus is "essential" at this point and can't die. But because he can't die and the only strategy he knows is "attack", he's going to bring all kinds of trouble down on your head unless you can run interference for him. Expect to see a lot of "Viranus Donton is unconscious" messages at the top of your screen.
The reason for this is that Viranus is clearly overmatched by almost everything in Nonwyll Cavern. The place is crawling with Trolls and Ogres with a few rats thrown in to keep life interesting, so you might be overmatched, too. I managed to raise my Restoration skill three or four times just off of healing him up after he went charging off. Me? I'm a sneak. You can't be damaged by things that don't know you're there.
The cavern itself is no great shakes aside from the critters. It's in two sections with a few side passages to explore. When you get to Galtus Previa, you'll find that he has gone the way of all flesh, though there is no clue as to what did him in. When you report back to Oreyn, you'll only be able to tell him that "there were creatures inside," but that's it. Oreyn doesn't like that story and wonders why he hadn't been eaten (Ogres and Trolls not being terribly picky about what's for dinner), but says that he'll look into it.
On that note, Viranus goes home, the contract is closed and Oreyn has more "duties" for you.
More Unfinished Business
Once again our favorite "eight-pint" warrior has defaulted on a contract. You're sent off to find out what's going on with Maglir (again). The contract was with a mage in Bravil, so that's where you'll need to start. If you happen to have 10 portions of Imp Gall stashed away somewhere, grab them. If not, you can go whack a bunch of Imps later.
When you arrive in Bravil, there is no marker for Maglir, so you'll need to ask around. Eventually you'll be pointed to the tavern where Maglir is staying and can talk to the little guy. How this plays out is going to depend upon how you handled his last defaulted contract. He'll be completely upfront about the fact that he has left the guild and is now with the Blackwood Company. If you gave him credit for completing his last defaulted contract, he'll refer you to the client (Aryarie at the Mages Guild, though she does wander) and be done with it. If you claimed the credit for the defaulted contract, he'll just clam up on you. In that case you'll either go back to Oreyn to get the name or get ready to talk to everyone in Bravil until you get the right one. Of course, since you're reading this, you can just head for the Mages Guild and find Aryarie, but that kind of takes the fun out of it.
Aryarie wants to know when she's going to get her Imp Gall and points you to Robbers Glen Cave (it's just off the road to the Imperial City, a little way north of Bravil). Robbers Glen Cave has 13 Imps scattered around, so coming up with 10 portions of Imp Gall shouldn't be that big of a deal. If you already have the Imp Gall, she'll be pleased as punch about it and will even throw in a ring with a leveled Shield enchantment in addition to the contract fee. If you have to go get the gall, she'll still give you the ring.
Oreyn promotes you to Defender and tells you that he's got an off-the-books mission for you. You'll need to talk to him at his house after hours, though.
Oreyn lives in a small house on the other side of the Chorrol Chapel. He fills you in on some of the background of the Blackwood Company. Specifically, he'll tell you about a failed mission to retrieve an artifact for a mage named Argoth from an Ayleid ruin called Arpenia, which is a little north of Nocturnal's Shrine, northeast of Leyawiin. Oreyn took 20 men into the ruin and lost 15 of them in the attempt to retrieve the artifact, including Vitellus Donton. The Blackwood Company came waltzing in and completed the contract. However it seems that Argoth and the artifact have both disappeared recently, so Oreyn suspects that it was a set-up and wants to investigate. He tells you that he can't order you to help him, but you might as well know that there will be no more contracts from Azzan or gro-Khash until you take the "I'm in" option for Oreyn and complete this mission.
You'll need to meet Oreyn at the Leyawiin Fighters Guild (he hangs out on he second floor balcony). Although you can walk to Arpenia from Leyawiin, this will be one of the few map markers that you can use immediately to fast-travel. Do so. Don't worry too much about Oreyn. He's "essential" throughout the whole thing, so he won't die on you.
When you enter Arpenia, Oreyn will stay behind you. There isn't anything much to fight, although there are quite a few chests and coffers and more than your fair share of traps. It took a little while before I found it, but there is a trigger in the first big chamber (near or on top of one of those "slam you into the spikes on the ceiling" traps) where Oreyn will tell you that the whole thing smells phony and that there must have been some sort of collusion between the Blackwood Company and Azani Blackheart, the Bandit who had the artifact they were tasked to retrieve. Oreyn believes that Azani has the artifact and wants to retrieve it. This will both complete the original contract for the Fighters Guild and also expose the Blackwood Company as a fraud.
Blackheart has this thing for Ayleid ruins and Oreyn knows of one a little ways north of Arpenia (what a coincidence), so you'll need to follow him to Atatar. You'll need to follow Oreyn this time. I find it to be a pain.
Somewhere between Arpenia and Atatar there is a Bandit. This Bandit is just an ordinary wimpy Bandit. However, this Bandit chooses the worst times to get hungry and go chasing after deer, so Oreyn goes chasing after the Bandit and you go chasing after Oreyn. And the annoying part is that the deer runs faster than the Bandit, but the Bandit runs faster than Oreyn, so all four of you (the deer, the Bandit, Oreyn and you) go running hither and yon until someone catches up with someone else. After a VERY brief fight, you have to spend the next several minutes staring at Oreyn's back as he goes back to walking to Atatar. You can't get very far ahead of him, you see, because he'll stop and wait for you to get within range again.
At any rate, you'll reach Atatar eventually. It's an Ayleid ruin with three levels and a couple of traps. There are Bandits scattered around the first two levels, but the last level was just Rats and Mud Crabs except for Azani Blackheart. Blackheart is a Redguard fighter (a few levels higher than you) with Elven armor and an encahanted Claymore.
And the artifact? Hmmmm. No mention of it, actually. Oreyn seems to more interested in Blackheart's ring than anything else and it's not even enchanted. No problem, though. You're promoted to Warder, the mission is done and you're able to get contracts from Azzan and gro-Khash again. You're free to leave the ruins whenever you'd like or go explore them more thoroughly. There are quite a few chests, several Varla Stones and maybe a four or a half-dozen Welkynd Stones to be had if you're of a mind to do it.