Amakumo Fruit is a new resource that was introduced to Genshin Impact in update 2.1. It is used as an Ascension material for characters such as Raiden Shogun. One of the most important things you will need to do is unlock one of the islands.
Seirai Island is the best place to farm this resource but is also engulfed by a massive storm that you will need to stop first. To do this, follow the Seirai Stormchasers quest and solve all the puzzles. At that point, you can safely explore the island and gather up all the resources that you need, located on the map below.
The central island is packed with Amakumo Fruit, and players can easily gather up more than 70 of them here. Keep in mind, each plant has two fruit on it, so make sure you double click each one. The plants can be hard to spot, as they tend to be pink and purple in color, much like the surrounding landscape.
The real trick to gathering any resource in Genshin Impact is to do it consistently. Even if you don’t need it right now, you certainly will in the future, so make sure you grab any Amakumo Fruit that you see as you wander around the game doing quests.