Most of you that have played the game will probably think this question has an easy answer. After all, the shadows are explained in the game. They were the minions of the witches of Orogg, sealed away by one of the three in that mountain forever. That's why they are only found around that mountain.
I thought so too, but then I realised something. This isn't entirely true, there is one other occurrence of shadows in the game. Its presence is often overlook since it comes after fighting through the entire shadow dungeon. I am of course talking about the shadow of the 7th king of Mercia.
This one shadow changes a lot lorewise. It means that people can get turned into shadows when they die and the shadows sealed away in the mountain might be shadowy souls too. This makes me wonder what they are. For the game they do count as undead and outsider. However, it also raises the question why Melporth is the only other shadow to be found outside of the mountain.
It can't just be corruption from Varannari witches, since during the game many cases of witches corruption can be found, but never a single other shadow. It also isn't that only the original witches of Orogg could create them, because in the temple of the lady of the night there wasn't a single shadow to be found either. Also the tomb of Melporth didn't include a special artifact that could be linked to his tranformation. The only thing unique was his sword, but that didn't have the aura of corruption that items from the witches of Orogg have, like the amulet of dark whispers. His background didn't mention anything special either, but that was to be expected since the background plaques are a bit biased.
So my main lore question is: What are shadows really? And how did Melporth become one?
Legends speak about an unarmored madman running around in the Wyvern mountains punching Wyverns to death