Shadow Power ?

[seewen13]

Many items refers to "shadow power".
It's look like a set of "the black.....", like:
http://te4.org/user/19353/itemsvault or http://te4.org/user/25294/itemsvault

Looking upon those items, it seems they are made for demonologist.
But I don't understand what is this "shadow power" exactly.

is it just the sum of these "+5 shadow power" that could bee seen on those objects ?

[Faeryan]

Afaik, it's the Demonologist only talent tree called Shadow Power.

[Kuroto]

The items with Shadow Power can be used by anyone. The set does seem more catered to Demonologists, but not entirely! The way it works is that each item in the set gives X amount of Shadow Power, and gains a bonus from how much Shadow Power you have across all items, such as a bonus to all saves equal to your Shadow Power, or a bonus to spell crit equal to half your Shadow Power.

[Doctornull]

is it just the sum of these "+5 shadow power" that could bee seen on those objects ?

Yes, you are correct. There are multiple items in the game ("The Black Socks", "The Black Eyepatch", etc.) which grant +x Shadow Power.

Afaik, it's the Demonologist only talent tree called Shadow Power.

There is no such tree.

Kuroto is completely correct.