I generally go for the satur with the healing aura until level 6, then I switch to Alpha wolf to get the +30% damage +20% chance to 200% critical.

On top of this I double it up with a crystallis which adds another chance for +30% chance to 250% critical hit. I generally go for movement speed and attack speed on this build, and I hide a lot, using wards, creeps or allied heroes to get sight on an enemy and move in from the blind spot, appearing from nowhere to Doom, death and scotched earth in that order.