Is that passive any good at all to sustain energy? I have invested 10 points into it and see no big difference - still often low on energy. Maybe it procs only from magical attacks? Anyway It seems that skill needs a buff.
It’s a one point wonder. If you mana issues i suggest you choose arcanist as your secondary class or slot in ectoplasms.
Unfortunately i already chose second mastery - Occultist. And I am using ectoplasm components as well. Just Amarasta’s Blade Burst takes too much energy for a melee class like Nightblade imo. Besides, Possession drains energy too.
I don’t think ABB synergizes well with Occultist. It’s primarily cold damage.
Not ABB but its connected skill - Lethal Assault is good for poison/acid Witch Hunter.
I’d recommend the Arcane Spark component. It has 45 energy leech per second IIRC, as well as a ton of OA.
Thanks for the advice I’ll give it a try.
P.S. But first I have to farm for Vengeful Wraith component to make Arcane Spark 
I have only 2 atm
Vengeful Wraith recipe can be bought from the Rovers.
Really. Now need some Chthonic Seals 
Cthonic seals drop from bloodsworn priests so often that I’m pretty sure each of them gets a dozen upon gaining their title.
I haven’t farmed seals in ages, but besides the grove the 1st half of tomb of korvaak is filled to the brim with cthonic humans you can get quite a few there
Already crafted Arcane Spark and it helps a lot with energy sustain!