This is one of the first quests offered by Ranis Athrys in the Balmora Guild of Mages once you reach the rank of Journeyman. This and the quest Manwe's Dues are offered at the same time, but are considered separate and will each raise your standing within the Guild.
Ranis will ask you to recruit a Telvanni named Llarar Bereloth in Sulipund. Unfortunately, if you cannot convince him, you must kill him.
Traveling to SulipundEdit
Ranis tells you that Sulipund is north of the Dunmer stronghold Marandus, and she marks Marandus on the map. If you have the Master Propylon Index, use the guild guide to Caldera and have Folms Mirel send you straight there. Otherwise, it's more complicated. The overland route doesn't really have a clear path due to mountains that complicate travel. Without levitation, the trip is very difficult, and far from Balmora. The other option is to take a silt strider to Suran, and then swim up the river that runs beside the town to Lake Nabia. Besides the occasional slaughterfish coming from the deep and the occasional cliff racer coming from above, there shouldn't be that much of a problem with creatures. Once you arrive in the lake, just get out on the shore and you'll be very close to Marandus. Then, just follow Ranis' directions to get to Sulipund.
Llarar BerelothEdit
Once you're inside Sulipund, just follow the winding hallway until you meet up with Llarar Bereloth. Talk to him, and at first he'll refuse to join the Mages Guild. At this point, you have three options, you can either kill him, use your Speechcraft skill to increase his disposition, or bribe him. Once his disposition is at 70, he'll join the Guild. Whether he's dead or has consented to join the Mages Guild, head back to Balmora and report to Ranis Athrys. If you were forced to kill him you will receive the lower Disposition award, and only two potions, rather than four.