Bluelithium's Improved Assassin

you ever wanted to play as a really cool shadow of death but always thought the assassin subclass was a little underwhelming? well this class is my solution to that problem and make that dream come true.

Assassinate

Starting at 3rd level, you are at your deadliest when you get the drop on your enemies. You have advantage on attack rolls against any creature that hasn't taken a turn in the combat yet. In addition, any hit you score against a creature that is surprised is a critical hit.

Analytical Eye

Starting at 3rd level, you can take the Search action as a bonus action on your turn. In addition, whenever you take the Search action, you can make an Intelligence (Investigation) check against a DC equal to the target's AC. On a success, until the end of this turn you can benefit from your Sneak Attack damage even without advantage on the attack.

Experienced poisoner

Starting at 3rd level, you have the ability to quickly coat your weapons in poison. You can use your Cunning Action to coat your weapons in poison using a bonus action.

In addition, you gain proficiency with the poisoner's kit. Whenever you concoct a poison, its save DC equal 8 + your proficiency bonus + your Intelligence modifier.

In addition you have learned how to properly coat weapons with these poisons allowing you coat twice as many slashing or piercing weapons or twice as many ammunitions. 

In addition, you can create one basic poison per day with no materials during a short/long rest.

quick escape

Starting at 9th level, you are difficult to pin down during a fight. You can move up to your movement speed as a reaction when an enemy ends its turn within 5 feet of you. This movement doesn’t provoke opportunity attacks.

In addition you also gain advantage on dexterity (acrobatics) cheeks to escape from a grapple.

Shadow walker

At 9th level, you master the art of the ambush. You can give yourself a bonus to your initiative rolls equal to your Intelligence modifier.

You are also adept at evading creatures that rely on darkvision. While in darkness, you are invisible to any creature that relies on darkvision to see you in that darkness.

in addition when you are hidden from a creature and miss it with a ranged weapon attack, making the attack doesn't reveal your position.

Poison Expertise

At level 13 you can now create one Serpent Venom per day with no materials instead of a basic poison during a short/long rest.

In addition  you have also learned how to make your injury poisons last far longer than most other poisons meaning they stay potent for up to ten minutes now.

In addition you can now also coat three slashing or piercing weapons with a single poison or up to nine ammunitions. 

 

Certain Death

Starting at 13th level you can choose a creature you can see within range and as a Bonus Action mark it as your quarry. you deal an extra 1d8 damage to the target whenever you hit it with a weapon Attack, and you have advantage on any Wisdom (Perception) or Wisdom (Survival) check you make to find it. If the target drops to 0 Hit Points you can use a Bonus Action on a subsequent turn of yours to mark a new creature.

In addition once on each of your turns when you miss with a weapon Attack, you can make another weapon Attack as part of the same action.

Death Strike

Starting at 17th level, you become a master of instant death. When you attack and critically hit a creature, it must make a Constitution saving throw (DC 8 + your Dexterity modifier + your proficiency bonus). On a failed save, double the damage of your attack against the creature.