Nightblade has Master assassin passive : incrase your physical and spell penetration against enemy you are flanking by 2974.
I not undestand definition of " flanking " help me please
This is a recent change and I have to say I like it because it does not require you to attack from Sneak (although it works perfectly fine from Sneak). In PvE overland or dungeons, I always stand to the back or side and it gives you a good damage boost by cutting through a significant amount of enemy armor -- also works in PvP naturally.
They also changed Silent Attack to Stun from Sneak or NOT! Just being to the back or side of an enemy will cause a stun.
My personal feeling is that the Devs are buffing some minor mechanics in the Nightblade skill lines to help Nightblades do Assassin-type moves and damage.
~ PS NA ~ ALDMERI DOMINION ~
IVY GOLDBLADE, WOOD ELF NIGHTBLADE
IVY GOLDBLAZE, HIGH ELF TEMPLAR
IVY GOLDBLOOD, HIGH ELF SORCERER