How do I unlock the hidden treasure in Seirai Island in Genshin Impact?

To unlock the hidden treasure in Seirai Island in Genshin Impact, you need to complete a series of tasks and puzzles that are part of the "Seirai Stormchasers" world quest. This quest involves dealing with the perpetual storm on the island and uncovering the secrets hidden within. Here is a detailed guide to help you through the process.

First, you need to start the "Seirai Stormchasers" quest by speaking to Katheryne in Inazuma City. She will direct you to a researcher named Eiko, who is located near the Koseki Village waypoint on Seirai Island. Eiko will explain that the storm on Seirai Island is caused by a powerful Electro energy source, and she needs your help to investigate and neutralize it.

The quest involves several steps, including activating and deactivating Thunder Spheres, solving puzzles, and defeating enemies. One of the key mechanics in this quest is the use of the Electrogranum, which you can summon from Electrograna plants scattered around the island. The Electrogranum will protect you from the constant Electro damage caused by the storm and allow you to interact with certain mechanisms.

To begin, you will need to activate four Thunder Spheres located around the island. These Thunder Spheres are marked on your map, and each one requires you to solve a puzzle or defeat a group of enemies. The puzzles usually involve using the Electrogranum to power up mechanisms or to reach high platforms. For example, one puzzle requires you to use the Electrogranum to activate a series of Electro pillars in the correct order. Another puzzle involves using the Electrogranum to create a bridge of Electro particles to cross a gap.

Once you have activated all four Thunder Spheres, you will need to return to Eiko, who will guide you to the central area of the storm. Here, you will face a powerful Electro Hypostasis boss. This boss has several phases and requires careful timing and strategy to defeat. It is recommended to bring characters with strong Pyro or Cryo abilities, as these elements are effective against Electro enemies. Characters like Diluc, Hu Tao, or Ganyu are good choices for this fight.

After defeating the Electro Hypostasis, the storm will dissipate, and you will be able to access the hidden treasure. The treasure is located in a cave beneath the central area of the storm. Inside the cave, you will find a luxurious chest containing valuable rewards, including Primogems, Mora, and rare artifacts.

Here are some important tips and considerations to keep in mind while completing this quest. First, make sure to bring plenty of healing items and food, as the constant Electro damage from the storm can quickly deplete your health. Second, pay attention to the timing of your Electrogranum usage, as it has a limited duration and cooldown. Third, be prepared for tough battles, especially against the Electro Hypostasis, and make sure your team is well-equipped with the right artifacts and weapons.

Common mistakes to avoid include not using the Electrogranum effectively, which can lead to unnecessary damage and frustration. Also, make sure to fully explore each area and complete all the puzzles, as missing even one Thunder Sphere can prevent you from progressing in the quest.

For team composition, it is recommended to have a balanced team with a strong DPS character, a healer, and support characters. For example, you could use Diluc as your main DPS, Barbara as your healer, and Fischl and Sucrose for support and crowd control. This team composition will give you the flexibility to handle both the puzzles and the combat encounters.

In terms of artifacts and weapons, focus on increasing your characters' damage output and survivability. For DPS characters, artifacts like Crimson Witch of Flames or Gladiator's Finale are good choices, while healers can benefit from Maiden Beloved or Ocean-Hued Clam sets. Weapons should be chosen based on your characters' abilities and playstyle, with a focus on increasing attack power and elemental mastery.

By following these steps and tips, you should be able to successfully unlock the hidden treasure in Seirai Island and complete the "Seirai Stormchasers" quest. This will not only reward you with valuable loot but also give you a deeper understanding of the lore and mechanics of Genshin Impact.