Both alchemical adepts and masters of stealthiness, Alchemical Assassins have focused their studies and training on how to improve their potionmaking and poisonmaking skills and how to use said potions/poisons to incapacitate their enemies.

Alchemical Apprentice

By taking this subclass, you gain proficiency in both the Alchemist's Kit and the Poisoner's Kit.

Expedited Replication

As an Alchemical Assassin, your Formula Journal is your most important tool, as it contains the recipes and formulas for any and every potion/poison you have ever made. When you take this subclass, you become doubly proficient in crafting elixirs that you are familiar with. If there is a potion/poison that you have confirmed its recipe (by either extensive research or previous experience in crafting it), you have expertise in making this potion/poison. When rolling to determine the outcome of the elixir-crafting process, you add your proficiency bonus twice to the roll.

Educated Guess

Starting at 9th level, in addition to any potions/poisons you create, you can spend some of your time during a short or long rest studying any possible ingredients you may have lying around. You can now make one poisoner’s check per short rest to understand what potion/poison any given combination of ingredients would make. Choose one catalyst and one reagent to study, and if successful in your poisoner’s check, you learn what potion/poison would be created if the two were combined, without expending either ingredient. (DC10 for petty, DC15 for mild, DC20 for potent).

Runic Enchantments

At level 13, you have become comfortable with the more mystical aspects of potion making. When crafting a potion or poison, you can expend extra materials to craft a Runic Seal and place it on the vial. 

Runic Seals:

• Silence: When a vial with this rune is broken, the glass makes absolutely no sound. Materials: Wax, any reagent used in making a potion/poison with the silence effect.
• Kindle:  When a vial with this inscription is broken, it sparks with fire, setting the contents inside on fire if flammable. Materials: Wax, ground-up flint
• More to come...

Muscle Memory

Through your extensive use of potions and poisons, you have become incredibly comfortable with handling them in combat, so much so that you can rely on your reflexes to use them for you. You can now throw or bash your enemies with your vials as a reaction, emptying their contents on a creature upon a successful improvised attack roll.