Heart of Watatsumi is part of The Moon-Bathed Deep subquest in Genshin Impact 2.1. There are multiple sub-quests in the Moon-Bathed Deep World Quests. These multiple sub-quests tell about the mythology of Watatsumi island and its people’s origins. This walkthrough demonstrates how to complete the Heart of Watatsumi to collect Spirit Pearl.
To get all the subquest you’ll need to speak with Tsuyoko, the Shrine Maiden of the Sangonomiya Shrine. First, teleport to the Statue of the Seven on Watatsumi Island and head up the hill to the West. You’ll see a ruined building and Tsuyoko standing off to the right. Speak with Tsuyoko to learn that Watatsumi Island is turning into a desert. To save the Watatsumi Island a sacred ritual needs to be done between the Sangonomiya and Enkanomiya.
The first part of this quest is to open the path to Enkanomiya, to do this you need to break the five seals on Watatsumi Island. You will automatically get four quests for the Eye, Fang, Fin, and Tail of Watatsumi after speaking with Tsuyoko. On completing these four quests you will get access to the Heart of Watatsumi sub-quest.
Heart of Watatsumi
“Heart of Watatsumi” is the final part of ‘The Moon-Bathed Deep’ World Quest Series. This walkthrough demonstrates how to complete the sub-world quest ‘Heart of Watatsumi’ and assist Tsuyoko in performing a ritual to save Watatsumi from turning into desert.
Return to Sangonomiya Shrine and talk to Tsuyuko
As you start the subquest ‘Heart of Watatsumi’, your first goal will be to talk to Tsuyuko at Sangonomiya Shrine. I have marked the location of the island on the map. Return to Sangonomiya Shrine and talk to Tsuyuko to report your progress. You can find Tsuyuko at the edge of the cliff.
Open the gate to the “Heart of Watatsumi”
Tsuyuko will ask you to follow her to complete the last task. She’ll lead you towards a location to the east where a water barrier is up. I have marked the location of the island on the map. From the cliff edge drop down to find another platform along the cliff wall.
Go to the “Heart”
Submit all the four Spirit Pearls at a phosphorescent wall and enter inside the cave.
Break the final seal
Inside you’ll find the ‘Heart’ of Watatsumi and more fish statue puzzles like the ones at the Fin of Watatsumi island. The big difference this time is that as you complete them water enemies will spawn.
There are four circular discs with fish statues and a circular stage in the middle. Activate the South, East, and West circles first. Rotate the fish statues so that they face each other that is looking inside the circle. After aligning fish statues, interact with the Mysterious Pillars. Eliminate all the water enemies.
Obtain the Key of the Deep
Once all fish puzzles have been completed and all enemies defeated you’ll get a short cutscene and then a prompt to obtain the Key of the Moon-bathed Deep. Speak with Tsuyoko to end the quest. You’ll earn the achievement of The Same Moonlight.