Sneaking drains your stamina while moving. The faster you move, the faster your stamina will drain.
Undead, daedra, and automatons are immune to sneak attacks. Some effects, such as Boethiah blessing and dagger specialization perks, will still increase your damage dealt to targets that have not detected you.
While dual wielding, your sneak attack modifier is reduced by half. This applies even if you are not performing an attack with both weapons.
The "Acrobatics" and "Shadowrunner" perks unlock the ability "One With the Shadows" Rank I and II, respectively. These increase damage dealt to enemies, but makes it easier for enemies to detect you.
If you are not invisible, you must be within 48 feet of the enemy. If you are invisible, you must be within 24 feet.
Damage mult is 1.5x for Rank I and 2.0x for Rank II.
The effect lasts 60 seconds.