This is a shared group task (a group is recommended in era), but can be technically be done solo.
Rewards: Chronobines, Iksar Left Upper Leg Bones, Experience, Faction
To obtain this task you’ll need to loot a Sealed Letter from a Sebilisian messenger in Field of Scale. Two different versions of Sealed Letter can drop. The one you need for this quest shows specific lore when you right click it. The Lore you’re looking for is shown below. This is a common drop.
Various a Sebilisian messengers can be found roaming around the zone. Some easy spot to get them are outside of Kurn’s Tower and near the fortress door in the Southeast.
Once you have the correct Sealed Letter give it to any of the major dragons in the middle of the zone to receive a pop-up box to select 1 of 3 tasks. Select Sarnak Recovery (Burynai)
Kill 3x a Sebilisian tracker. These can roam around so a tracker can be helpful. I found a pack of 3 in the southwest area, and a pack of 2 in the north. They be both Iksar and Chokadai models.
Find “an escaped sarnak” type mobs. Get them to low HP (sub 20%) until one of them provides you an update. It is recommended to not use mercenaries or pets to tank or you may not get an update. A tracker can help locate them as they are spread around the zone.
Locate “meeting place” (see map). It is out on an island in the water. While here, kill a Sebilisian emissary.
Hail Trakanon to complete the task.