I said Dark Souls for a variety of reasons.
Bows - in Dark Souls have range advantage even without a hawk ring. They have magical/elemental damage potential without needing to buy DLC. They are capable of HEADSHOTS, and the dragonslayer bow staggers and has knockback every time.
Skyrim can have 3x sneak attacks, move while aiming, slow time, and paralyze before the arrow even hits due to bad scripting though so it may be about even here. Plus the whole fortify X crap that makes you able to have AR of 300+.
Shields - (most) Shields in DS have 100% physical damage mitigation, as well as built in magic/elemental res. You also don't get staggered or guard broken easily even from giant demon hammers etc with 40 END and good stability shield. Some shields even block all status ailments on an enemy weapon. i.e. you won't be able to bleed or poison someone if they block with the Artorius greatshield. Also you can PARRY AND REPOST. Since Skyrim has only a scant few types of attack and no combos to speak of, the battle would be over after a few seconds EASILY.
Skyrim can shield charge, and use spell breaker. So once again it might be close as DK gets tossed into the air on impact.
DK has backsteps, rolls, and flips.
Skyrim has none of the above.
DK has the ability to use 2 handed weapons with one hand and a shield, or a one handed with two hands. Also a way larger variety of weapons of all sizes and ranges. It even has SPEARS and THROWING WEAPONS. As well as a variety of armor with POISE so that even if Dovakiin got a hit in it would probably be shrugged off.
Skyrim has a bugged HA perk that doesn't reduce stagger at all, and very limited armor choices that have no inherent resists to non physical dmg. Damage reduction on Shields and armor is capped at 80% no matter how OP you smith them up.
DK has the gear to negate all sound, turn almost invisible, disguise as a tree etc. to perform high damage back stabs. Which can be performed with almost ANY weapon, no matter how large.
Skyrim has sneaking for up to 30x damage with a dagger. Unlike npcs, I think it would be hard to get behind a DK hero creeping along or rolling along in plain sight. Unless you become invisible due to high sneak skill arbitrarily.
DK can be level700+ with a crapton of defense and HP, access to all magic and miracles. Any form of attack is equally valid at any time. Also due to the high level, illusion and paralysis spells probably wouldn't work.
Skyrim can be 81, and have infinite magic, summon dremora, use shouts to spam knockback. Necromage would apply as DK is undead though. SLOW TIME WOULD PRETTY MUCH END THE FIGHT RIGHT OFF THOUGH.
DK can summon 2 allys
Skyrim can have a whole entourage with various exploits, but they are generally underleveled and weaker than Dovakiin.
Perhaps the most relevant point however is that when DK dies, they pop out of the last bonfire. When Dovakiin dies they have to reload, so even if it was a tie DK wins by default.
