Umbral Assault:
Quest: Damage enemy Heroes with Crescent Slash.
Reward: After hitting 30 enemy Heroes, increase the damage of Crescent Slash by 33% and the duration of its slowing effect by .5 seconds.
Reward: After hitting 60 enemy Heroes, the cooldown of Crescent Slash is reduced by 2 seconds.
Lesser Foes:
Shadow Strike does 300% increased damage to minions and mercenaries and its cooldown is reduced by 6 seconds if it only deals damage to minions and mercenaries.
Eye in the Dark:
While in Stealth, your personal vision radius is increased by 30% and you can see over terrain.
Watcher's Warding:
Every 15 seconds, and every time you enter Stealth, gain a Ward charge. Stores up to 5 charges. When you would take damage from an enemy Hero, a Ward charge is consumed, granting you 40 Physical Armor if that damage was from a basic attack, or 20 Spell Armor if that damage was from an ability, for 1 second.
If she is supposed to be a warrior, even a bruiser type warrior, stealth seems to clash with that identity. since you still want to absorb damage and be a distraction. Becoming invisible, especially to empower abilities, sounds like she should just be an assassin.
I really like the idea of how your stealth works though. its very different to the passive/active stealths we have in the game already, as its sitting somewhat in between.
Her Q fits quite well, but since it can stun/cc I would just recommend maybe 2 seconds longer on cooldown., especially since you have a lvl 1 talents that can reduce the cooldown.
Her W fits very well, but as an assassin. A bruiser wants to be in your face, but you get a higher bonus on its dmg for being further away, kinda counter synergy.
Her E is excellent, except how stealthed E doesn't have a cooldown, meaning you can just jump across an entire team over those 3 stealthed seconds and just instantly start the fight on their back line. For Sonya, to gap close that much she would need to use Leap and land her Q, which at least you can see her doing. Even Valeera, an assassin can only gap close (if talented) an average ranged autoattacks distance.
Avatar of vengeance is iconic to wardens and you made a good design. Just to clarify though, where is the Avatar? is it looming over Maeiv and copies her abilities on top of herself? or do you summon the avatar elsewhere, in which case can you move it around or is it stationary? I just need clarification, thank you! Other than that it may just last a tad to long, since it can get a lot of damage off, amazing concept for Vengeance though!
As for her second ult, Im a little worried, i like the idea, but 160 second cooldown is a bit ridiculous. Tyrande has almost the same thing, on a 30 second cooldown. Since it reveals i understand making it longer, but it also only has temporary stealth. May i suggest reducing the Cooldown to maybe about 40 seconds? and instead of a global reveal (you can add that to the level 20 if you really like that aspect) make it like you reveal enemy heroes in a large area?
Honestly its an amazing concept, Well done.