I read a novel series of something similar a few years back, was an actual ebook I got from amazon I think though. Let me see if I can remember the name.... Found it, first book is called Skinwalker (Jane Yellowrock is name of series) by Faith Hunter. Problem is, it's not a LN and it's not free, and the protagonist is female. I did enjoy the first 3 books, 4th one wasn't out when I read it last though.
you mean an actual skinwalker as in 'evil Navajo witch (can be male or female) who curses and kills others and uses the skins of animals to change into their shape,' or ones where they call themself skinwalker or walker? Just curious cause I only know of the Jane Yellowrock and Mercy Thompson series and neither MC is evil, male, or Navajo. mostly you read about skinwalkers or wendigo in urban fantasy stories as a criminal, villain, or enemy of the protagonist. I don't think I've ever seen a story written from their pov.
He's looking for an MC, good luck finding a book or LN with an actual evil MC. I suppose there's a few out there though, never heard of an evil Navajo witch protagonist though. One of the Iron Druid Chronicle books the MC had a fight with some wendigos though.
more like the monstrous version of them that are barely sentient if you have good books with them as the antagonist thats fine too