In Astria Ascending, speak with Magter in Arktan Valley after obtaining Zimar as a party member to receive the Weakness of the Noises side quest.
Talk to the hermit of the Swamps
Fast travel to the Vetira Entrance in The Swamps and speak with Sietach on the western side of the first area.
Defeat 9 Heygs
…
Defeat 6 Tufas
The Tufas can be found in Peyska Spring Sewers.
Defeat 3 Warabes
The Warabe can be found in Peyska Spring Sewers.
Rewards: Sheratan x1, Ether X x3, Mirror Shield x1 and 5,000 Lums