The Fylgja - Personal Spirit
Each person has a fylgja, a personal spirit companion appearing in animal or female form.
The fylgja is a personal spirit, often appearing as an animal reflecting one's nature or as a woman. It can be seen by those with the sight, especially at moments of death or danger. The fylgja represents the deeper spiritual aspect of the self.
Your fylgja walks beside you; those with sight can see its form.
The fylgja represents part of the complex Norse soul concept.
Various Sagas
Written about in
- What the Havamal says about knowing yourself
A companion spirit takes a form that matches your nature. That makes it, in effect, a portrait of yourself you did not get to choose, which is a fair definition of the thing self-knowledge is after.