Amakumo Fruit is a Local Specialty that can only be found in Inazuma’s Seirai Island, this materials has only one use so far, which is to ascend the five star character Raiden Shogun, there can only be a total number of 95 Amakumo Fruits on the map at one time, and once you collect one of them you will need to wait 3 days for them to respawn again.
Amakumo Fruit Information
Characters that use Amakumo Fruit for Ascension
Amakumo Fruit Map Location
You can find this map by going to Teyvat Interactive Map website and search for all the materials you need, note that once you farm one of these Amakumo Fruits you will need to wait 3 days for it to respawn again.