Sneak

Destined to Fail
Without the first perk in the Sneak tree, your odds of being detected are tripled. Which typically results in making sneaking around impossible.

Sleeping Targets
In Requiem, somewhat realistically you deal 100x more damage to a sleeping target, which is particularly useful if you feel like assassinating someone.

Sneak Attack Immune
A lot of higher level creatures in Requiem are immune to taking additional damage from sneak attacks, you will still have 'sneak attack was successful' messages from the way it was coded, but you will only deal normal damage. Here is a list of creatures which are immune:


 * Storm Atronach
 * Flame Atronach
 * Frost Atronach
 * Death Hounds
 * Almost everything found in Soul Cairn
 * Dragon Priests
 * Dwarven Centurions
 * Dwarven Spiders
 * Dwarven Spheres
 * Ice Wraiths
 * Almost all variants of Skeletons
 * Almost all variants of Spriggans
 * Wisps

Notice almost all of these creatures lack vital organs.

Armor
In Requiem what weapon you choose has an impact on how effective it is, blunt weapons do better armor penetration as a trade-off for being slower, etc. A lot of seemingly impossible enemies in Requiem in fact just have really high armor, and seeing as armor can give up to an 85% reduction in damage, this is a mechanic you cannot ignore. I might do a write up of what is effective against certain enemies.

Damage Resistance
Simply put, this is the value that when multiplied by * 0.12 gives the total percentage of physical damage to be resisted, most of this value is from armor, creatures like Draugr have armor added to them in the form of Damage Resistance. You can read more about it here.

Rank 1

 * Description: You know the basics of moving silently and are harder to detect when sneaking while not wearing any heavy armor.


 * Effect: Removes the penalty for sneaking, and adjusts your skill to behave as if you had 15 extra points in it.

Rank 2:

 * Description: You are even harder to detect when sneaking while not wearing any heavy armor.
 * Effect: Adjusts your skill to behave as if you had 35 extra points in it.

Note: Removes the penalty even if you are wearing heavy armor, but the increased odds to not become detected only apply if you are not wearing heavy armor. Higher ranks overwrite the lower ones.

Deft Strike

 * Description: You've learned to exploit weaknesses in your foes' armor when sneak attacking with daggers, bows or swords.
 * Effect: Sneak attacks with Crossbows, Bows, Daggers, and Swords will gain 50% Damage Resistance penetration on targets within 512 units of you.

Anatomical Lore

 * Description: New found knowledge of humanoid anatomy allows you to slay almost any human-like creature outright with sneak attacks.
 * Effect: Against humanoid targets, Crossbows and Bows will deal 200% more damage in sneak attacks, while everything else will deal 500% more damage.

Advanced Anatomical Lore
Note: This overwrites the previous perk Anatomical Lore, an odd behavior considering most perks in requiem only do that when they are ranks in the same perk.
 * Description: Your vast knowledge of anatomy allows you to perform devastating sneak attacks on almost any target.
 * Effect: Against all targets, Crossbows and Bows will deal 200% more damage in sneak attacks, while everything else will deal 500% more damage.

Muffled Movement
Note: Does nothing to change your audible noise. There is a passive effect in the mod called PerkMuffledMovement that would reduce your audible noise by 50%, but it is not being added to your character ever and is going unused. I assume this might be an oversight from the mod author.
 * Description: Your new found finesse allows you to move more quietly while not wearing any heavy armor.
 * Effect: While not wearing any Heavy Armor, adjusts your skill to behave as if you had an extra 15 points in it. Stacks with similar effects.

Light Steps
Note: Interestingly, all pressure plates are scripted to check for this perk on the target actor before activating, most perks in Skyrim operate on an active effect that is hidden from your UI, while this one is simply a conditional boolean statement in the scripts. This means if you had a mod and that author did not setup a proper script on the pressure plates he added, they would still trigger. This is because Pressure Plates themselves are just regular objects or areas that execute scripts when actors enter their boundaries, so they need scripts to function. I just found it interesting so I thought I'd share. In fact, Requiem has several 'invisible' pressure plates, but in reality there are no pressure plates there, just scripted behaviors being executed.
 * Description: By distributing your weight more consciously, you are able not to trigger any pressure plates or similar mechanisms.
 * Effect: Does exactly what it says.

Acrobatics
Roll Triggering Abilities: Werewolf Howl, Shield Bash Disarm, Spell Impacts, Dragon Tail attacks, Mammoth Attacks, Giant Frostbite Spider attacks, certain unique Troll NPC attacks (added by Requiem).
 * Description: You're quite acrobatic, allowing you to roll forward silently, to avoid non-magical knockdowns and to move even more silently.
 * Effect: While not wearing Heavy Armor, adjusts your skill to behave as if you had an extra 10 points in it. Stacks with similar effects. Adds a passive roll that prevents you from being being knocked over by a lot of spells/abilities that would normally knock you over, see the list below. This makes fighting many creatures a lot more manageable. I believe an animation is played when Roll is triggered (needs verification).

Shadowrunner

 * Description: There's almost nothing you cannot evade. You are even harder to detect, more quiet and all falling damage is decreased.
 * Effect: While not wearing Heavy Armor, decreases your overall chance to be detected by 10%, adds another bonus to your Sneak skill as if you had an extra 10 points in it, and reduces fall damage by 25%.