This quest only occurs if the player allowed Sledrig or Volgaafsonaan to survive, or if they persuaded Helvana that killing them both was the correct thing to do.
24 hours after the quest "A Dragon's Dirge" is completed, the next time the player reaches a settlement, a Courier will approach and deliver a letter from Sledrig, Volgaafsonaan, or Helvana.
Reading this letter will give the player an objective to return to them.
Sledrig will be found in his Sanctuary, which will now be lush and green.
He will tell the player the Sanctuary now belongs to them; it has changed because it now represents the player's vitality.
He also gives the player a tablet to teach the player the Shout "Summon Sledrig".
If Volgaafsonaan is also alive, Sledrig will tell the player that the dragon wishes to speak to them as well, and they'll receive a new objective to speak to Volgaafsonaan.
If Sledrig is Empowered, he will speak of the player as if they are beneath him and tell the player that he is going out into the world to find new purpose. Sledrig will then leave the sanctuary and the player will never see him again as he's off living the rest of his life.
Volgaafsonaan will be found in his Lair (the player will have found a back door to it on their way out to speed up getting to him).
He will grant the player a tablet to learn the Shout "Call Volgaafsonaan", which will cause him to come to the player and help them, similar to the base game Shout "Call Dragon".
If Sledrig and Volgaafsonaan were killed, and Helvana was Persuaded, Helvana will be in Sanctuary and tell the player that she's informed the college of Sledrig's absence and that the Sanctuary now belongs to the player.
After conversations, the quest will complete.