User blog comment:Kenetron/Urvyne, the Winged Blades man/@comment-7709681-20140725051345

Innate - The true damage isn't much (But could turn problematic with a bit of Attack Speed), but that passive, the mana steal, should be an unique secondary passive (An passive instead of an active ability), too powerful against any mana dependant unit, specially knowing that all the mana stolen is granted to you to use and is in the same kit as the ultimate's passive component (read the ultimate's notes).

Q - That passive component turns ridiculous while having at least 50% Crit. Chance, you could end up with 500 AD later game without building damage; again, as with the innate passive's mana steal, it could be tolerable only if it where an unique passive without active. Nothing to say about the active.

W - A gap-closer, not too much to be said here; maybe the damage is too high, but that could be just me who thinks so.

E - The ability doesn't detail the stealth duration, only the fading time after its short deactivation.

R - This ability's passive component, in conjuction with the innate passive, will make laning with the player a nightmare, you don't only replete your resources but deplete those of the opponent aswell. And the active is partially tolerable, partially because it may be excessive to have the ability reduce itself on every kill/assist while having that damage.