Y

 is an item used to craft.

Obtaining
Y can be obtained by using an on a. A Wai is spawned when 2 s come into contact, which can happen after they are lead to each other with.

Synthesizer v2
Up to 30 Y can be placed in to gain  per item.

Synthesizer v3
Up to 40 Y can be placed in to gain  per item.

Essence Crafting
Y can be used to add Stars to Shimmering Light Armor.