There are five Sanzhani that you can find on the map of The Blood of Dawnwalker. Each Sanzhana will allow Coen to send a letter to Lunka, either to gain information about her hostage situation or to simply convince her that everything is going to be okay. After completing all five Sanzhani quests, you will also get The Tsarina's Favorite Human achievement in The Blood of Dawnwalker. Additionally, these little moth fairies will reward Coen with something you can't get anywhere else: +1 day extra time before Brencis' coronation begins. Yes, they literally shift time.
Here are all five Sanzhani/Sanzhana locations in The Blood of Dawnwalker:
From the Sandy Gorge Shrine, if you go east towards the ravine, you may come across a glowing mushroom ring. Interacting with this will trigger the Good Home quest.
Go to the Small Bridge Shrine (it may be a Destroyed Shrine for you) on the southern part of Briar Sloughs, then cross the river to find an abandoned camp. Follow the trail using Focus Mode to find a Sanzhana location in The Blood of Dawnwalker.
Go to the center of the Altenmarkt, and you will hear the Sanzhani, triggering a quest. You need to go up the balcony and enter the house to find the little moth fairy.
From the Silty Mug Inn, follow the road to the east until you see two large leafless trees to the north, across an area with a small bridge. Go there to find another Sanzhani location in The Blood of Dawnwalker.
In the northern part of Rockfalls region, head to the Boarback Trail Shrine (it may be a Destroyed Shrine for you), then head north to the woods. You will find the final Sanzhana somewhere here.
Here are some other The Blood of Dawnwalker guides for your perusal: how to romance Anca, how to romance Lacra, should you free Mert in the Under Watchful Eyes quest, and how to increase ability slots.
سەرچاوەی فەرمی بە زمانی ئینگلیزی: https://gamerant.com/the-blood-of-dawnwalker-all-sanzhani-locations-letters-to-lunka-quest/