I have a nightblade(amarasta’s) and i want some versatility so i take occultist and. wendigo .
The skill is just tremendous with amarasta’s it become an AOE , the damages early levels are pretty huge and cherry on the cake it even works on undead.
The only minor problem is that you don’t leech that much life and some necromancers are pretty resistant to the skill.
Amazing skill, one of the most interessant i have seen so far ,A++.
Try to combine it with a Curse of Frailty (and link it to it), you won’t be disappointed turning your hard debuff into hard debuffing tons of damage 
I prefer melee bro , but thanx for the advice .
CoF is a very good debuff for melee or range, and if you link Wendigo Mark to it, more monsters will be touched by the proc, hence more life steal for you
I don’t deny the efficiency of COF .But i like attaching a devotion combat skill on my main attack and proc it .
I find it kinda cool , im a simple man:)