Dark Cloak used to purge but it got nerfed a long time ago.
I remember that one morph used to have something like this. One morph of Cloak had guaranteed crit on next attack, and the other was a defensive focused one, that was removing harmful effects (I think it was like 5 negative effects or something). And important part - both were giving you invisibility, just like Shadow Cloak / Shadowy Disguise does.Dark Cloak used to purge but it got nerfed a long time ago.
What effects are you talking about? To clear roots / snares, use Race Against time, Phantasmal Escape or Shuffle. To gain speed, dodge roll with a bow. To deal with damaging effects, just heal through them. If you do solo PvE you might wear Pale Order, for example (or not - see below). Magicka nightblade has more native skills that heal you while doing damage, although DW also gives you some of that (Bloodthirst, Blood Craze and the ultimate). I don't really notice effects in PvE at all other than roots / snares, but if you do in the content that you do, may also be able to make something of that via CP, for example with Survival Instincts CP.I am a stam NB using DW and 2H sword. She has just about come to her end of life now having completed almost all of the PVE stuff soon. Not being able to deal with negative effects has been my one issue with my NB but I was planning on starting a new one. I believe I am running Hundings Rage and Night Mothers Gauze mix and it does quite well. I can survive solo PVE but effects just irritate me and was hoping something had changed that maybe I missed before I roll another NB. My Templar, Neco and Warden can all deal with effects as they have skills so when I switch to playing my NB I realize how much I use those. Thanks for the info!