Ritemaster Iachesis

Ritemaster Iachesis is an Altmer and the leader of the Psijic Order. He is initially encountered outside the Ceporah Tower on Artaeum.

The Queen's Decree
The Vestige must travel to the mysterious island of Artaeum and speak to Ritemaster Iachesis about their recent discoveries in Summerset.

The Queen's Decree
Outside the Ceporah Tower:

Valsirenn: "And there was no sign of Leythen. I don't know whether to be grateful or concerned."

Ritemaster Iachesis: "We'll find him, Val. Now go check on the pearl while I speak to our new guest."

When speaking to him:

"What a rare honor Valsirenn bestowed upon you. Only a select few not of our order have ever walked upon this sacred island. Val tells me your aid was indispensable in uncovering the false Aldarch's plot on Summerset."
 * We discovered that newcomers to Summerset were being murdered to power the abyssal pearls. "Unfortunate, certainly. The magic you describe sounds familiar, though I can't quite recall where I've heard of it before. I fear the pearls may be a harbinger of the threat Sotha Sil warned us about."
 * Sotha Sil? What threat? I don't understand. "Sotha Sil, one of the living gods of the Dark Elf Tribunal. He's an honorary member of our order. After an attack on his Clockwork City, he warned us about a Daedric threat to Summerset and Artaeum. I sent Valsirenn to investigate."
 * Is there anything more I can do to help? "Indeed, but not until we finish studying the pearl Valsirenn brought us. There are mysteries to unravel and Val believes you will be instrumental to our success. We can get started immediately, unless you want to explore our island first."

If the dialogue screen was exited:

"Strange magic. Life-stealing pearls. Unknown sea creatures. It all relates to Sotha Sil's warning, but we still don't know what form the real threat will eventually take."
 * Is there anything I can do to help deal with this threat?

If the final dialogue option is chosen, Iachesis will simply say the line that he would have said initially, had the Vestige chosen to ask him about the how to help prior to completing the quest.