idk how but i have 10 already and i need some more but I have no idea what drops it and my bestiary doesn't have any info on them.

They drop from the lantern thingys.....I know the cave in Northen part of Kamuso village....umm....the Iwgana one I think? has them

They drop from the creepy lanternes that can burn themselves and tackle you. they normally have really low hp / defenses but they can kill you in one hit if you're not careful.