The Fossegrim is a friendly male Water Spirit that sits at the bottom of a waterfall and plays the fiddle with amazing skill. He can only be found at night time and can teach you how to play the fiddle with amazing skill just like him.
The Fossegrim originates from Scandinavian Folklore, he is a friendly spirit and has no intention of killing anyone, every Thursday night people give him a food offering so they can be taught how to play the fiddle just like him, if the offering isn’t substantial enough he will only teach you the basics of the fiddle like how to tune it but if the offering is satisfying to him he will grab your hand and make you play it till you bleed. Once your hand is bleeding you will be able to play the fiddle so well anything/anyone will dance to the sound of your fiddle. If you want to learn instantly or have him play your tunes that you have made, he requires you to sell him your soul in return for his service but he will not harm your soul in doing so.
They are the best fiddle players in the world having no one being able to match their skill, their music can mesmerise anyone no matter how strong their mind is making them really powerful but they are not violent so will never use it hurt people, they can teach anyone no matter how bad how to play the fiddle if the offering is substantial enough.