Plaguemaster

Poisonous wizardry

When you choose this arcane tradition at 2nd level, you gain proficiency in the poisoner's kit. You also gain the poison spray cantrip if you don't have it already. Whenever you cast a spell that deals poison damage, you can add your intelligence modifier to the damage roll (minimum of 1).

Sickening Aura.

Staring at 2nd level, whenever you cast a spell that deals poison damage, you can emit an aura that lasts until the start of your next turn. Whenever a creature other than you starts its turn in the aura (30ft centered on you) They take poison damage equal to your intelligence modifier (minimum of 1).   

Minions of disease

Starting at 6th level, you add the spell find familiar to your spellbook, but you can only summon diseased giant rats. On the rats turn, it can take the attack action. The saving throw for the disease is your spell save DC.

Superior poisons

Starting at 10th level whenever you make a poison using the poisoner's kit, you can use your spell save DC instead of the normal required saving throw. Also, the poisons do not wear out after a certain amount of time. 

Magical plagues.

You master you spell casting with plagues. Starting at 14th level, you add the spell Contagion to your spellbook.  Also you are immune to poison damage, the poisoned condition, and disease. Also, you can add 1d4 to the damage of the sickening aura.