Odral Helvi - House Hlaalu Caldera Quests
Odral Helvi is found in the Governor's Hall of Caldera on the 2nd floor and will offer you House Hlaalu quests if you're the rank of Kinsman or above. For all of Odral's quests you can speak with Crassius Curio in Vivec if you want to help House Hlaalu instead of Odral. Essentially, Odral is a corrupt member of House Hlaalu and doing quests for him help him personally... Unless you turn over evidence/report to Crassius each time you accept a new quest from Odral.
Odral Helvi Quest #1 - Sealed Orders
All you have to do for this quest is deliver the sealed orders to Tenisi Lladri who is found in the House Hlaalu Canton of Vivec. In order to reach her you'll have to go through the Hlaalu Waistworks into the Hlaalu Treasury then finally into the Hlaalu Vaults which is where you will find her. If you'd like to see a video on how to get to Tenisi Lladri follow the link.
Of course your alternative turn in for this quest is Crassius Curio in Hlaalu Plaza. Odral is corrupt and asks you to do things that benefit him.
Odral Helvi Quest #2 - The Caldera Spy
For this quest you will need to speak with Elmussa Damori in Caldera. Raise her disposition to 80+ and she will tell you that she stole the documents. There are many different things you can do with the quest right now including killing her, which will make Odral the happiest. You can also return to Crassius and ask him what to do.
When you return to Odral you can lie to him about where you got the documents and if you have a disposition of 70+ he will believe you, otherwise you will have to tell him it was Elmussa.
Odral Helvi Quest #3 - Erroneous Documents
There are a couple different courses of action for this quest as well, what we're supposed to do is go to the Hlaalu Records office in the Hlaalu Canton and steal the real record/replace it with the fake. To reach the Hlaalu Records you'll want to go into the Hlaalu Waistworks then into Hlaalu Treasury, from here you'll be able to get into the Hlaalu Records and the Hlaalu Vaults.
Now, depending on what you choose to do the quest branches out a bit. If you want to actually replace the documents and help Odral then use Sneak/Chameleon and open the small chest on the bookshelf in Hlaalu Records (pictured above). You will need to take the real deed and replace it with the fake.
Alternatively, you can turn the fake land deed over to Crassius in Hlaalu Plaza or to Rovone Arvel. If you turn the fake deed over to either of these two you'll need to have a real deed made to trick Odral. To do this head over to Baren Alen in the Hlaalu Vaults (pictured below) and talk to him after giving Crassius or Rovone the fake deed.
Warning: I don't know if this quest is what did it but I think it was. When I went to buy the Land Deed from Baren Alen for the Hlaalu Stronghold quest it wasn't for sale. I think it's because I bought a Land Deed from Baren Alen while doing this quest.
UESP Erroneous Documents Entry
Video Walkthrough of Erroneous Documents Quest
Odral Helvi Quest #4 - Rent and Taxes
This quest can be extremely easy if you want it to be. After accepting it speak with Odral again and pay the 100G he wants immediately to end the quest. He'll be upset with you the farmers weren't killed but you'll only get a -5 disposition which isn't a lot.
Alternatively you can hunt down both Manat Varnan-Adda and Llovyn Andus and demand they pay. Neither will be able to pay but you can take Llovyn's pet Guar and sell it for 200G if you'd like which will cover the debt of both farmers. You can find both of these farmers near the Dren Plantation which is a little bit west of Suran.
Note: Speak with Crassius Curio in Hlaalu Plaza or Rovone Arvel near the Arvel Manor for an alternative way to complete this quest
Odral Helvi Quest #5 - Shipment of Ebony
Much like all of Odral's quests you have multiple routes you can take with this one. If you wish to help Odral then take the raw ebony to Drinar Varyon in his house in Ald'ruhn. You can find Drinar's house just north of the Mage Guild and right across from the Silt Strider.
Alternatively, deliver the shipment to Crassius Curio in Vivec and he will tell you to take it to Segunivus Mantedius in the Buckmoth Legion Fort south of Ald'ruhn. Fastest way here is to use Divine Intervention in Ald'ruhn, that will take you right outside of the building with Segunivus in it.
If you decide to take the ebony to Segunivus instead then return to Crassius Curio in Vivec to complete this quest. Odral will be removed from the game once you turn over the ebony to Segunivus.