Nightshade

Your focus is on the deadly qualities of both natural and unnatural toxins and venoms. Rogues of this archetype are often alchemists, apothecaries, gallipots, physicians and sciolists who relentlessly strive to unlock the secrets of poisons and how they affect the body. Daggers and arrows are just the vehicle to deliver your true weapon: the lethal concoctions of your noxious art.

Bonus Proficiencies

When you choose this archetype at 3rd level, you gain proficiency in the Medicine skill and the poisoner’s kit.

Poisons

When you choose this archetype at 3rd level, you learn to apply poisons through "Poison Applications".

Poison Applications. You have 3 Poison Applications, each of which are expended when you use them before making an attack. You regain all of your expended Poison Applications when you finish a short or long rest.

You gain another Poison Application at 5th, 11th and 17th level.

Poisons. You have learned to create three poisons of your choice, which are detailed below. Many poisons enhance an attack in some way. You can use only one poison per attack.

You learn two additional poisons of your choice at both 7th and 10th level. Each time you learn a new poison, you can also replace one poison you know with a different one.

Saving Throws.  Each of your poisons require your target to make a Constitution saving throw to resist the poison’s effects. The saving throw DC is calculated as follows:

Poison Save DC = 8 + your proficiency bonus + your Intelligence modifier

Blinding/Deafening Poison

You can expend one Poison Application to apply a poison that can inhibit the hearing and sight of the target. The target is deafened and has disadvantage on all Wisdom (Perception) checks based on sight until the start of your next turn.

Additionally, on a failed saving throw, the target is blinded until the start of your next turn.

Burning Blood Poison

You can expend one Poison Application to apply a poison that can boil the target’s blood, causing a great amount of pain. The target takes 1d6 poison damage.

Additionally, on a failed saving throw, the target takes 1d12 poison damage instead.

Crippling Poison

You can expend one Poison Application to apply a poison that cripples the targets mobility. This poison attacks their muscle system causing them to drop whatever they're holding in their hands.

Additionally, on a failed saving throw, the target falls prone until the start of your next turn.

Decaying Poison

You can expend one Poison Application to apply a poison that can prevent the target from healing. The target is unable to gain hit points until the start of your next turn.

Additionally, on a failed saving throw, if the target would heal it takes that much damage instead.

Disorienting Poison

You can expend one Poison Application to apply a poison that can disorient the target. The next attack roll against the target has advantage if the attack is made before the start of your next turn.

Additionally, on a failed saving throw, the target’s next attack will be made at disadvantage if the attack is made before the start of your next turn.

Frenzy Poison

You can expend one Poison Application to apply a poison that can enrage the target, sending it into an uncontrollable frenzy. The target recklessly attacks with no care for its well-being until the start of your next turn. Any attacks the target makes during this time will be at advantage, while any attacks against the target will be at advantage as well.

Additionally, on a failed saving throw, the target’s frenzy is so deep that it attacks the creature nearest to it, friend or foe.

Mindfire Poison

You can expend one Poison Application to apply a poison that can slow the target’s mind, making it more difficult for them cast and concentrate on spells. The target has disadvantage on concentration saving throws until the start of your next turn.

Additionally, on a failed saving throw,  the target may only cast a spell if has not used a move action or bonus action. If it has cast a spell this turn, it may not use a move action or bonus action. This lasts until the start of your next turn.

Slowing Poison

You can expend one Poison Application to apply a poison that can slow the target. This poison weakens the target’s ability to move and react, reducing it’s movement speed by half.

Additionally, on a failed save, the target is unable to take reactions until the start of your next turn.

Splash Poison

You can expend one Poison Application to apply a poison that will erupt on impact allowing you to hit two targets simultaneously. The target along with another target within 5ft take 1d4 poison damage.

Additionally, on a failed saving throw, they both take an additional 1d6 poison damage.

Inoculation

Starting at 9th level, your practice and exposure to toxins is so incredible that you have been able to self-administer toxins in minute amounts in order to build up a tolerance. You gain immunity to poison damage and the poisoned condition.

Penetrating Poisons

At 13th level, your study of poisons has become so intense that you are able to create poisons which ignore the natural defense of many creatures. When you deal poison damage to a creature, you may ignore its resistance to that damage. Additionally, no effect may give that creature advantage on saving throws against your Poison Applications.

Venomous Virtuoso

At 17th level, when you roll initiative, if you do not have any Poison Applications, you gain one.