Can I turn the difficulty up higher than Master?

Question

My first character is a level 60 high elf with 100 destruction, conjuration, heavy armor, smithing and enchanting. A room full of the 'most elite' type of whatever threat is around just doesn't faze him anymore. He's getting bored with his high elf existence, and asks your help to make his world more exciting!

Is there a console command, configuration entry, or mod that can pump the difficulty to 11?

PS: for details on how difficulty affects gameplay see this question.

Answer 1

With Patch 1.9, yes you can. (without mods or console commands)

Patch 1.9 adds a sixth difficulty level: Legendary. It reduces damage dealt by the player to x0.25 and increases damage taken by the player to x3.

If you want to make the game harder, focus your skill points and perks on non-combat skills: Speech, Pickpocket, Lockpicking, etc. You can also put skill points and perks on combat skills that you won't be using in combat. This will level up your character (which will make enemy level difficulty scale to your level), while at the same time, not make your character stronger for combat.

With the Dragonborn DLC installed, perks may be undone and redistributed at the cost of one dragon soul per skill tree.

At the end of the At the Summit of Apocrypha quest, you will have access to different portals (one for each skill) which allows you to clear and regain any perks in that skill tree, at the cost of one dragon soul. You remove all perks from a single skill perk tree and can use these reclaimed perks on unlocking any perks you wish, including perks taken from said perk tree. By reading the Black Book, Waking Dreams, you can return to Apocrypha and alter the skill trees whenever you wish.

Mods for turning the difficulty up can be found in my answer to the question, "How to make Skyrim more challenging at higher character levels?"

^{Sources:
http://www.uesp.net/wiki/Skyrim:Combat#Difficulty_Level
http://www.uesp.net/wiki/Skyrim:Skill_Perks#Perks
http://www.uesp.net/wiki/Skyrim:Patch#Version_1.9}

Answer 2

There are three possibilities using the console:

Advancing your level

The UESP page for console commands suggests using advlevel to increase your character's level, which will then increase the difficulty of enemies. Since advlevel doesn't give you more perk points or health, stamina, or magicka, it effectively increases the difficulty of the the game.

So, to increase the difficulty of the game by one level, open the console and do:

player.advlevel

Repeating the command will increase the difficulty several notches. However, there's some belief level scaling stops at level 54 or so, so this might not help.

Changing your attack damage multiplier

Consider from the the answer to the other question about what effect difficulty has on your character:

Difficulty | Damage Dealt | Damage Taken
-----------------------------------------
Novice     | x2           | x0.5
Apprentice | x1.5         | x0.75
Adept      | x1           | x1
Expert     | x0.75        | x1.5
Master     | x0.5         | x2

If you want to pump up the difficulty another level (let's call it Grand Master), you'd want to cut your damage dealt by another 0.25x and the damage taken by 0.5x:

Gd. Master | x0.25        | x2.5

You can achieve the first part (damage dealt) the console to modify your attack damage modifier. Effectively, all you should need to do is half your attack damage multiplier using setav¹:

player.setav AttackDamageMult 0.5

To change the damage taken, you'll need to change your health or your resistances, which is explained in the next section.

Changing your other stats

You can get finer control by modifying your player's actor value indices, like changing your melee and unarmed damage or your resistannces.

First, get the current value using getav:

player.getav MeleeDamage
player.getav UnarmedDamage

Then, set your damage multiplier to something else using setav¹:

player.setav [Insert half the value of your current MeleeDamage here]
player.setav [Insert half the value of your current UnarmedDamage here]

Then, using getav again, record the values for the following resistances:

player.getav DamageResist
player.getav FireResist
player.getav ElectricResist
player.getav FrostResist
player.getav MagicResist

Halve the values you get here, and set them to the new values using player.setav¹.

Alternatively, you could just set your current total health to half its current value:

player.setav Health [Insert half of your current total health here]

Setting your player scale

yx. mentioned in the comments that people have found setscale will affect the amount of damage you do: decreasing this value should decrease the amount of damage you do. However, it also affects other things not normally affected by difficulty, including your physical size and your run speed.

You can find out your current scale by using player.getscale.

^{Note 1}setav just lowers your base stats: your items will wind up making the effects of the modification less potent. Changes to stats modified with setav also persist after reloading. If you want to force your stats to take a certain value, regardless of what items you have (and have it persist through sessions), use forceav instead.