The Mountain seems like he is pretty strong and well versed at man-to-man combat, but Aragorn has defeated many a troll and orc by himself.
The Mountain vs Aragorn
Both are emotionally and physically damaged and have a weakness for the protagonist. Choose your side!
Voldemort vs Darth Vader
This is for the Star Trek fans. On planet Vulcan during their mating ritual, who would win in the the ritual Kal-if-fee fight to the death? #fight