So I got an idea for a really good character but I need light 2H sword for this. And I wanted to ask : What is known about ebony blade? What perks does it use?

Try http://www.lauraleeburch.com/blog/wp-content/uploads/2011/11/tiny-knife-from-India.jpg-e-450x270.jpg.

If you mean Mephala's artifact, it's kinda bugged.

http://uesp.net/wiki/Skyrim:Ebony_Blade

Thanks Captain, I mean - has anyone tested what affects it?

Every death caused by that sword triggers a woman to make disturbing moans and sadistic comments about your victims.

You shouldn't just disregard help people try to give you - the answer that you probably need is included in the Bugs section of the UESP article.

''The Ebony Blade is wielded in two hands, but is considered a http://uesp.net/wiki/Skyrim:One-handed sword rather than a greatsword. This means that it gets the benefits of a generic http://uesp.net/wiki/Skyrim:Two-handed weapon, such as using and training the two-handed general skill level, but also benefits from all the one-handed perks that apply to one-handed swords. Specifically, its damage, weight, weapon reach, sound files, impact force, and stamina usage are all configured to one-handed skill values. It also receives damage bonuses from http://uesp.net/wiki/Skyrim:Fortify_One-Handed enhancements on the player's gear.''

The woman that moans, and sadistic comments is Mephala... It sounds to me, like she is getting it on with another Daedric Prince, perhaps Sheogorath, at a game of checkers...?