Quote Originally Posted by Tiaexz View Post
After checking Wiki:
Alright, those NPC's were mentioning him with good reason, however, there is more than one Undefeatable Foe it seems, there are 8. So you might not have fought the one I did.

I fought the one North-East of Whiterun, in the Mountain.
Yep, different ones then. Mine was west of Solitude. 8 sounds like the proper number to drop complete sets of both light and heavy armor, with each one holding one piece.