Bloody Pox works as a secondary or third damage source with proper items support. It’s main role however is debuffing monsters and spreading offensive procs. This is how it works in my Vitality caster/Doom Bolt conjurer. Maybe you can make some kind of mean Poison caster build with transmuted Dreeg’s Evil Eye and Bloody Pox as an acid source of damage with items like that, that and spice it up with the lucky Conduit of Eldritch Whispers craft. Or just use it with Ravenous Earth as Ritualist.
-You can’t take Possession and Harbinger of Souls, one exclusive skill only. I recommend Possession in this case.
-No Curse of Frailty/Vulnerability? It provides resist reduction which is a multiplier to your damage.
-Only one point in Blood of Dreeg? It provides OA, health regen and an on demand heal.
-Why the points in Reaping Strike/Necrotic Edge? Are you planning on using your sceptre for attacks? You have no attack replacer and only a single one-handed weapon. Your weapon damage is going to be struggling.
-Similarly, Solael’s Witchfire/Second Rite provide little for a caster. I recommend picking between melee and casting. Your points here and in Reaping Strike/Necrotic Edge are wasted while you are not attacking (i.e. doing caster things).
-Your gearing choice is odd as well, I get the feeling you were trying to stack % Chance to Hit Vitality/Bleed procs between Abyssal Mask, Fiendscale Jacket and Boneweave Leggings for a sort of gimmicky melee/caster tank hybrid but it will be just that - a gimmick.
Well you could go nightblade for Phantasmal Blades for max bleeding on a single target or transmute it to aid in the trash cleaning but bloody pox although powerful, is only a support skill since it lacks power against bosses
Pox with the dark one set is like you never seen before. For trash - its single target damage is still below average and a single target skill is needed to support it. Something like doom bolt, ravenous earth or acid purge