Galaxy Guardian

The Galaxy Guardian is a mysterious entity found deep within the Void Cave of the Crimson Sakura Isles.

He allows the player to craft Galaxite, and other ores that are key components to craft it.

He is hidden away in the Void Cave. From spawn
follow the path leading to Shogun
then when you come to the bridge leading to the Shogun Island go to the path on the left side
The Cave entrance will be in the wall hidden by purple leaves. To open the door of the Cave the player needs Dynamite from Silas.

No quest on the wiki is given by this NPC.

He one of the few NPCs that get there dedicated quest unlock and area.