Welcome!
Fade has always been giving DR% by hard point. Max it, the earlier the better. You will need the DR% for survival. If Venom works with DT (I have no experience with kicksins), you should use Cloak of Shadows, as it gives you poison pierce here. I would put 5-10 hard points into it, no more because of the diminishing returns. (Lvl 1: 25% - Lvl 10: 65% - Lvl 20: 77% - Lvl 50: 88%)
I wouldn't bother with Mind Blast or Blade Fury. Mind Blast can be good as a 1 pointer for trash control, but it's easier to simply kill them usually. You probably need a dedicated blade sin to have a useful damage with Blade Fury (again, no experience with them, just a guess)
Use claws with shadow +skills and lots of poison skill damage % for Venom prebuffing.
I don't know much about the Shadow summons, if you have spare points spend them on the Master.