Nerthus

A goddess who is often forgotten, and who shouldn't be. Who is perhaps best known for representing valour, holiness and fertility. Shown veiled or masked. And also represented by boars, birch forests, swamps and wetlands among other things.
I'm not actually a practitioner of Northern traditions, but I do know a lot of people who are, and some of them are champs are absolute champs. :)
This is the cover art for a devotional being written by
Nicanthiel's website, and information on the book, can be found here.