The invisible tutelary spirit -a guardian spirit that protects an area, or a person. Sometimes these spirits will protect a full lineage of people or culture- of Norway.
There are some stories of Flygia and the Dopplesauger being connected.
The idea of a spirit being and a person being connected for the person’s entire life isn’t uncommon. Its very common at the moment to believe in a Guardian Angel.
In Roman times the idea of a guardian spirit was very common it was called a Daimonion in Latin.