some skills i have some doubts:

1) aura of darkness: Decrease the attack power of enemies who come within range. Does not work in PvP. This skill has a 3 seconds cooldown.

tested this skill : and do nothing, the amaunt of damage from enemies(monsters) is the same damage.

2) aura of weakness: Decreases the physical defense of enemies who come within range, thus making it useless to the Night Shadow. This skill does not work in PvP.

tested this skill :and do nothing, the damage i do is the same to enemies(monsters).

3) curse of blood: Restores HP in the amount of damage that would be dealt. This skill does deal a small amount of damage -- roughly 10,000 in PvE and about 2,500 in PvP. This skill has a cooldown time of 300 seconds.

didn´t test this one, is it flat damage skill? at level 1 for exemple what damage is done and what is received ? its says power 2400 is it right? so do 2400 damage at level 1 skill ?, and i drain 2400 damage from monsters?

4) screaming soul: Confuse and drain souls from your target some surrounding enemies. No effect in PvP or PvE, No souls consumed. Player uses regular attack when skill is used. This skill has a 60 second cooldown time.

didnt test this one, like mass drain ? what is confuse target (stun)? No effect in PvP or PvE (lol)

5) soul injection : Take control of a monster and have it attack for you

didnt test this one, and the monster stops attaking ?, and it attack others monsters whit me ? like mercenaries ?example : can i control all shinx comanders in the top room of tomb ? (to good to be true

Decreasing physical defense on mobs would help in a party.
Mana Break for knights (and Mana Break 2 for templars), apart from dealing damage, also
decreases the target's magical defense, which doesn't help the TK/knight himself, but it does
help magic dealers hitting the same target. The same idea applies to the aura for NS.

1. This skill works fine. Aura must land on a monster before it lowers damage - its actually a debuff, not self buff.

2. Worthless, unless maybe you are in party or plvling a physical class ;P.

3. Yes, damage is fixed. At lvl 1 you can drain 2400 hp, at lvl 4 - 5600. Very useful when you get 100% cast (no more hp stealers or even hp pots).

4. AoE, confuses monsters around, skill needs 2 souls to cast. Confused monsters stop attacking you and start attacking each other. You can still use normal attack on confused mobs, but skills attacks wont work till Screaming Soul expires. Personally i rarely used it, but it can save life.

5. Monster should stop attacking you and start act like a mercenary (not really worth it, damage is too low, but funny to watch).
Unfortunatelly soul injection was broken recently (or "fixed" depending on point of view...) - monster stops attacking and does nothing, besides duration is so short now (6 min game time), that it became completely useless.