System Basics

Terminology

 Skyrim Hero  Hero System
 Damage Health  Killing Attack
 Damage Stun  Blast, HTH, Normal Attacks
 Toughness  Average of Normal PD & ED
 Damage Resistance  Resistant Protection (rPD)
 Magic Resistance     Resistant Protection (rED)
 Stun  STUN
 Health  BODY and Health/2 = CON
 Stamina  END and some STR
 Magicka  END Reserve (Only For Magic)

There are two approaches to adapting this setting.

  1. Adapt Skyrim to Hero System
  2. Adapt Hero System to Skyrim
The first is the easiest. Make some races, create the magic system, and then off you go. Hero and Skyrim have a lot of similarities and thus this will work fairly well. If you group is experienced with Hero, this approach makes a lot of sense. 
The second is a bit more challenging, however with a result that will more closely match Skyrim and thus be more accessible to new Hero players. This approach leverages the Toolkit aspect of Hero, allowing you to tweak the rules to fit the setting.
The second is my preferred approach, even though I am a veteran Hero player. There is an elegance to the Skyrim CRPG that I think would work well at the table. Enhance it where necessary to support the flexibility of tabletop play, but don’t clutter the game with needless complexity. 
A tall order, to be sure.

Characteristics

 Characteristic  Base  per Level  Description
 Health (HLT)  20  +2  Vitality index. When Health = 0, character is dead. If Stun Damage received in single hit > Health/2, character is “Stunned”. Max 50.
 Stun (STUN)  20  +4  Pain index. When Stun = 0, character is unconscious. Max 50.
 Stamina (STA)  20  +4  Fatigue index. When Stamina = 0, character is Fatigued and loses 1d6 Stun per 2 Stamina lost/used after 0.
 If Health Damage received in single hit > Stamina/4 +5, character is knocked down. Max 50.
 Magicka (MAG)  0  +4  Magical power index. When Magicka = 0, character cannot cast spells. Max 50.
 Physical Recovery (PREC)  4  Perk  The amount of Stun and Stamina recovered during a Recovery. Max 10.
 Magicka Recovery (MREC)  4  Perk  The amount of Magicka recovered during a Recovery. Max 10.
 Toughness (TGH)  2  +1  The amount of Stun Damage reduced from each hit as well as the amount of Health Damage from each Damage Stun attacks. Max 10. 
 Offensive Combat Value (OCV)  0  Perk  The bonus added to each attack roll. Max 3.
 Defensive Combat Value (DCV)  10  Perk  The target for an opponent’s attack roll. Max 13.

Skills

Skill rolls are 3d6 + Skill vs. 10. 10 or higher is a success. This is known as the “Roll High” option for Hero. All skill and combat modifiers work as written. 
Conversion is:
15 = +0 
20 = +1 
25 = +2 
30 = +3 
40 = +4 
50 = +5 
60 = +6
70 = +7 
80 = +8 
90 = +9 
100 = +10

Powers

In general, Characters cannot purchase powers without GM approval. 

Damage Resistance 

Damage Resistance reduces Health Damage and Stun Damage from all non-magical attacks. The shorthand for Damage Resistance is DR.
Cost: 3 character points per +2 Damage Resistance

Poison Resistance 

Poison Resistance reduces effect of all poison attacks. The shorthand for Damage Resistance is PR.
Cost: 1 character point per +1 Poison Resistance

Damage Stun

Damage Stun must be defined as either Physical or Magical with a specific special effect (e.g. Steel, Elven, Blunt, Shock, Frost, Flame, etc.). The Health and Stun damage from the attack is reduced by the sum of the appropriate Resistance (Damage, Magic, Poison) plus Toughness. 
Damage Stun causes Knockback. 
Cost: 5 character points per 1d6 and is ranged;
Common Limitation:
Hand to Hand Attack -1/2 (no range, no knockback, adds to Unarmed Strike Damage)

Damage Health

Damage Health must be defined as either Physical, Magical, or Poison* with a specific special effect (e.g. Steel, Elven, Blunt, Shock, Frost, Flame, Poison, etc.). The Health damage from the attack is reduced by the appropriate Resistance (Physical or Energy) only. The Stun damage from the attack is reduced by the sum of the appropriate Resistance plus Stun Resistance.
Damage Health causes no Knockback. 
Cost: 5 character points per 1d6 and is ranged; *Poison is a +2 Advantage
Common Limitation: 
Hand to Hand Attack -1/2 (no range, adds to Unarmed Strike Damage, Unarmed Strike Damage cannot more than double the damage from this power). 


Effect/Damage

One of the fundamental tweaks is the simplification of damage in Skyrim Hero. All damage is done as “Normal Damage” in
Hero System. This means that the sum of the dice equals the STUN damage, and the amount of HEALTH is determined based on the values of the dice: 1s = 0 HEALTH, 2-5s = 1 HEALTH , and 6s = 2 HEALTH. 

For example, a
Firebolt: Damage Health 6d6 (Magic Flame) results in 6, 5, 3, 3, 2, 1, equalling 20 STUN and 6 HEALTH. Looking at the dice, the 6 is worth 2 HEALTH, the dice valued at 2-5 are worth 1 HEALTH each (total 4), and the 1 is worth 0 HEALTH. Both Damage Resistance and Toughness would reduce the STUN, while only Damage Resistance would stop the HEALTH damage. If the target had Toughness 4, Magic Resistance 2, and Magic Resistance 2 (Flame Only) he would reduce the STUN damage by 8 and the HEALTH damage by 4, thus suffering a total of 12 STUN and 2 HEALTH. 

Unarmed Strike Damage

Damage Stun 2d6; All characters begin with the same base damage for unarmed strikes.

Stamina Strength Table

Stamina Lift
0 50
2 54
4 57
6 62
8 66
10 71
12 76
14 81
16 87
18 93
20 100
22 107
24 115
26 123
28 132
30 141
32 152
34 162
36 174
38 187
40 200
42 214
44 230
46 246
48 264
50 283
52 303
54 325
56 348
58 373
60 400

Lift

Lifting costs 2 Stamina. A character may Push his Lift by 20% for each additional 1 Stamina spent (max +5 Stamina which doubles Lift). 

Encumbrance

Standard
Hero System rules using the Lift value on the chart.

Initiative

Since Dexterity isn’t used, everyone essentially has the same Initiative. This isn’t inherently a bad thing. It also provides the opportunity to capture one of the subtler elements of
Skyrim weapon speed.
When a combat Phase begins, the GM asks the group to declare if they are going to
Move Only,
Hipshot, or
Hurry. Once that is known, the order of actions proceeds based on weapon/attack type.
 INIT  Action
 10  Move, drop item
 9  Unarmed attack
 8  Dagger, Single Spell
 7  Shortsword, Load Bow
 6  Sword
 5  War Axe, Mace, Double Spell
 4  Greatsword, Load & Fire Bow
 3  Battleaxe
 2  Warhammer
 -1  Power Strike (reduces base INIT)

Move Only allows a character to move, possibly performing a Defensive action. Even if the character Holds half of his action he cannot attack with it until after everyone else has gone in that phase.
Hipshot will increase your Initiative by +1 with a -1 OCV to any Attacks
Hurry will increase your Initiative by +1d6 with a -2 OCV to any Attacks
If a character choose to Hold Action, he may interrupt any subsequent character’s action by winning a Contest of Initiative. This is resolved by rolling 3d6, highest roll wins, with ties indicating simultaneous action.  

Power Strike

Power Strike is -1 OCV, -1 DCV, +2d6 Damage strike costing 4 extra Stamina. Axes and Two-Handed weapons do an additional +1d6 damage for +2 Stamina.