Trebonius Artorius Quests, (Vivec Mage's Guild)

Disappearance of the Dwemer - Your first quest to discover whatever happened to the Dwemer.
 Trebonius Artorius in the Vivec Guild Hall will first ask you to investigate the disappearance of the Dwemer (or so misnamed as Dwarves). He doesn't seem to have a good idea on how to do this, though he suggests you speak with 
Edwinna at the Ald'ruhn Mages guild.
In previous Mage Guild quests ( Excavation Report , Dwemer Blueprints of Mzuleft , and Dwemer Ruins of Bethamez ) you may (or should have) picked up three different books related to the Dwemer: Hanging Gardens , Egg of Time , and Divine Metaphysics . You may have also already talked with Hasphat Antabolis (bottom of the Balmora Fighters Guild) or Senilias Cadiusus (Dwemer ruin of Nehuleftingh, North East of Suran) who mention that Hanging Gardens may be a key to dechipering the other two books. Since this book is in Aldmeris, you still need to find someone who can read it.
Talk to Edwinna, Antabolis and the wizard Divayth Fyr about the books and you will be pointed to a fellow named Yagrum Bagarn (Divayth and Yagrum are related to the main quest and are found in Tel Fyr, South West of Sadrith Mora). Note that I couldn't get Edwinna or Antabolis to mention Divayth, Yagrum or Baladas (though Divayth does mention Yagrum, though not where he is until you are the correct point in the main quest). Baladas Demnevanni can be found in the tower in Gnisis (dome structure North West side of town). You may also be pointed towards a Telvanni sorcerer Baladas Demnevanni (unknown location?). Once you talk to them about the Disappearance of the Dwarves , the book will be translated for you. Yagrum can be found in the bowels of the Corprusarium deep beneath Tel Fyr. Although I visited Yagrum and talked to him about the three books and the disappearance of the Dwemer, the books were not translated for me (though he does give a very brief overview of each book, as well as going into detail about the disappearance).
At any rate, if you ever do translate the books, return to Trebonius for a large increase in disposition with him and the guild. Even though I didn't official get the books translated by Yagrum, I was still able to complete the quest.

Kill the Telvanni Councillors - A strange request from the guild master to kill all the Telvanni councillors.
Trebonius Artorius in the Vivec Guild Hall will only give this quest to you if you have reached the rank of Warlock and finished the main quest. The request is simple, merely kill all of the Telvanni councillors (since you've done the main quest you should know where all of them are). A rather strange request, but hey, he's the boss (for now anyways). Unless you'd rather not kill them, there's no real downside to killing them all. The councillors in brief are:

1. Master Aryon in Tel Vos (Upper Chamber)
2. Mistress Dratha in the Upper Tower in Tel Mora
3. Mistress Therana in the Upper Tower of Tel Branora
4. Master Neloth in Tel Naga (Sadrith Mora)
5. Master Baladas in Arvs-Drelen (Gnisis)
6. Gothren in the Upper Tower of Tel Aruhn (probably already dead)
Of course these are all powerful mages and many of them well guarded, so its not an easy task, but one that you're probably up to at this point.
If you complete his request and return to Trebonius, he will reward you with his staff and Necromancer's Amulet.
 
Trebonius' Staff 
Type: Blunt Weapon, Two Handed 
Chop: 2 - 16 
Slash: 3 - 16 
Thrust: 1 - 10 
Condition: 900 / 900 
Weight: 16.0 
Value: 10000 
Cast When Strikes 
Weakness to Fire 7 to 15% for 6 secs in 5 ft 
Weakness to Shock 7 to 15% for 6 secs in 5 ft 
Fire Damage: 7 to 15 pts in 5 ft 
Shock Damage: 7 to 15 pts in 5 ft 
Charge: 6500 / 6500 

Necromancer's Amulet 
Value: 240 
Constant Effect 
Resist Normal Weapons 25% of Self 
Fortify Intelligence 25 pts on Self 
Restore Health 1 pt on Self 
Spell Absorption 25 pts on Self