Assassination Rogue

Assassination Rogues are experts in toxins who specialize on giving their victims a slow insidious death.

Poison Knife

Starting at 3rd level, you gain proficiency with the poisoner's kit. In addition, as a bonus action you can apply a deadly toxin to your weapon, The toxin replaces your Sneak Attack Damage and it can only be applied to a melee weapon, This toxin last for 1 minute or until you hit with your weapon once which changes to two attacks if you apply the Toxin to a dagger. The poison ignores immunity to the poisoned condition, and its save DC is calculated as follows:

Toxin save DC = 10 + Inteligence Score + Proficiency bonus

When you use this feature, choose one of the following:

• Instant Poison: A creature subjected to this Toxin must make a Constitution saving throw, if it fails the target takes an extra 2d6 points of acid damage from your attack.
• Deadly Poison: A creature subjected to this Toxin must make a Constitution saving throw, if it fails the target its poisoned and it takes 1d12 points of necrotic damage at the start of his turn, If you attack the same creature with this Toxin and is still poisoned you add a 1d12 to the Toxin damage die. The creature can make a constitution saving throw at the end of its turn to end the effect.
• Wound Poison: A creature subjected to this Toxin must make a Constitution saving throw, if it fails the target takes 2d4 points of cold damage and is unable to heal his wounds for 1 rounds 
• Mind-Numbing Poison: A creature subjected to this Toxin must make a Constitution saving throw, on a fail the target its poisoned and whenever it tries to cast a spell it must succeed on a intelligence saving throw (Toxin save DC) on a fail it takes 1d8 points of Psychic damage and it will fail to cast the spell, This effect last until the start of your next turn.
• Crippling Poison: A creature subjected to this Toxin must make a Constitution saving throw, if it fails the target takes 1d8 points of Lightning damage for every 10 points of movement it uses, this effect last until the start of your next turn.
• Anesthetic Poison: A creature subjected to this Toxin must make a Constitution saving throw, If it fails, at the start of his turn it gains dissadvantage on attack rolls and at the end of the turn it falls unconscious until the end if his next turn.

Remorseless Attacks

Also at 3rd level, whenever you attack with a dagger as a main weapon you do an additional 2 points of damage, In addition if you attack a creature with a poisoned dagger you will gain an additional 5 feet of movement for that turn. At 9th level the damage of this feature is increased to 4 and the movement is changed to 10 feet.

Mutilate

At 5th level You learn a new technique to use on combat, This technique can only be used if you are holding two daggers. Whenever you attack a distracted creature you can choose to use this feature instead, Using both your action and bonus action you can perform an attack roll aiming with both weapons directly into the weakpoint of a target. On a hit, You will deal your main weapon damage and an additional 1d6 points of damage per unique Toxin in your daggers, In addition this attack will apply both your weapons Toxins into the victim. (The target will have to roll only 1 saving throw)

Malice

At 9th level A creature affected by one of your Toxins will have dissadvantage on the saving throw if you succesfully hit him while hidding, In addition in your first turn of a combat you can apply 1 Toxin to a weapon as a free action. Also your Poison knife Toxins damage is upgraded, and if you apply the same Toxin to your weapon twice they are enhanced for your next attack. Your Toxin damage are upgraded as follow:

• Instant Poison: The damage roll changes to a 4d6, If you enhance this Toxin the damage die becomes a d8. [At 13th level the damage die increases to a 6d6]
• Deadly Poison: The damage roll changes to a 2d12, If you enhance this Toxin the creature will have dissadvantage on all saving throws as long as he is affected by the Toxin. [At 13th level the damage die increases to a 3d12]
• Wound Poison: The damage roll changes to a 4d4, If you enhance this Toxin the moment you hit with you'r weapon the creature will not be able to perform constitution saving throws until the start of your next turn. [At 13th level the damage die increases to a 6d4] 
• Mind-Numbing Poison: The damage roll changes to a 2d8, If you enhance this Toxin the creature will take 2d8 points of damage from the attack and it will not be able to use spells for the duration of the effect. [At 13th level the damage die increases to a 3d8]
• Crippling Poison: The damage roll changes to a 2d8, If you enhance this Toxin the creature will lose half its movement and it will take damage for every 5 feet of movement he uses, in addition the creature will only be able to use 1 attack per turn. [At 13th level the damage die increases to a 3d8]
• Anesthetic Poison: It now adds 2 points of exhaustion to the target, If you enhance this Toxin the creature will gain 1 extra point of exhaustion when he wakes up from the unconscious effect. 

Cold Blood

at 13th level, whenever you successfully hit a creature you will have the option to make the attack a critical Hit at the cost of getting 3 points of exhaustion, However If this attack succesfully kill the creature you will only gain 1 point of exhaustion instead. In addition, if you critically hit and the weapon used is a dagger with a Toxin, The creature will not be able to make a saving throw to nullify the effect of the toxin.

Hunger for Blood

At the 17th level, Whenever you attack a creature affected by your Toxins they take an additional 2d6 points of necrotic damage, If you critically hit and the weapon used is a dagger with a Toxin the damage of the poison will be doubled as well. In addition whenever you kill a target you will gain 1 extra action and bonus action to use on the same turn, This feature can't happen more than once per turn.