Some rogues spend much of their time in labs and workshops, crafting bombs and brewing elixirs.  These alchemist agents can use their talents to heal and remove maladies from their allies or add an explosive element to their repertoire of skills.

Alchemy

When you reach 3rd Level you gain proficiency in alchemy supplies.  In addition, as part of a Long Rest, you may use alchemy supplies to create up to four alchemical items of your choice (choosing from alchemical bombs you know and alchemical elixirs.)  Alchemical items remain potent for 24 hours, after which point they become inert and worthless.  The number of alchemical items you can create as part of a Long Rest increases by 1 when you reach 7th Level (5), 13th Level (6), and 19th Level (7).

Alchemical Bombs

Starting at 3rd level, you learn how to create two types of alchemical bombs selected from the list below.  Alchemical bombs can be thrown as an Action to a point within 30 feet.

1. Fire Bomb - Each creature in a 5-foot-radius sphere centered on that point must make a Dexterity saving throw. A target takes fire damage on a failed save, or half as much damage on a successful one. The fire spreads around corners. It ignites flammable objects in the area that aren’t being worn or carried.
2. Frost Bomb - Each creature in a 5-foot-radius sphere centered on that point must make a Constitution saving throw. A target takes cold damage and its speed is reduced by 10 feet until the start of your next turn on a failed save, or half as much damage on a successful one.
3. Shock Bomb - Each creature in a 5-foot-radius sphere centered on that point must make a Dexterity saving throw.  Targets of this bomb have disadvantage on the saving throw if they are wearing armor made of metal.  A target takes lightning damage and it can’t take reactions until the start of its next turn on a failed save, or half as much damage on a successful one.
4. Stink Bomb - Each creature in a 5-foot-radius sphere centered on that point must make a Constitution saving throw. A target takes poison damage and is Poisoned until the start of your next turn on a failed save, or half as much damage on a successful one.

The saving throw DC for your bombs is 8 + your proficiency modifier + your Intelligence modifier.  These bombs’ damage is equivalent to your Sneak Attack damage.  Using a bomb counts as using your Sneak Attack.

You learn how to create an additional type of bomb at level 6th level (3), 9th level (4), and 12th level (5), 15th level (6), and 18th level (7).

Alchemical Elixirs

An alchemical elixir can be administered to yourself or another creature within 5 feet of you.  When you administer an elixir, you choose one of the following effects:

1. Healing - As an Action you inject the target with a healing tonic. The targeted creature restores Hit Points equal to your Sneak Attack damage.
2. Antidote - As a Bonus Action you inject the target with a cleansing serum. The targeted creature can make an immediate saving throw with Advantage against any one poison or disease currently affecting it.
3. Stimulant - As a Bonus Action you inject the target with an invigorating tonic. The targeted creature can take the Dash or Disengage action on its next turn as a Bonus Action.

Mixology

Starting at 9th Level, using alchemy supplies you can change one type of alchemical bomb in your possession to another type of alchemical bomb that you know as a Bonus Action.  When altered in this way, the alchemical bomb becomes unstable - if it is not used within one minute the bomb becomes inert.  Also at 9th Level, when you learn a new bomb you have access to the following additional options.

1. Acid Bomb - Each creature in a 5-foot-radius sphere centered on that point must make a Constitution saving throw. A target takes acid damage immediately on a failed save and additional acid damage equal to the number of Sneak Attack dice at the end of its next turn, or half as much damage on a successful one.
2. Concussive Bomb - Each creature in a 5-foot-radius sphere centered on that point must make a Constitution saving throw. A target takes thunder damage and is knocked prone until the start of your next turn on a failed save, or half as much damage on a successful one.
3. Tangle Bomb - Each creature in a 5-foot-radius sphere centered on that point must make a Dexterity saving throw. A target takes fire damage and is grappled until the start of your next turn on a failed save, or half as much damage on a successful one.  The Escape DC is equal to your bomb's DC.
4. Thunder Bomb - Each creature in a 5-foot-radius sphere centered on that point must make a Constitution saving throw. A target takes thunder damage and is deafened until the start of your next turn on a failed save, or half as much damage on a successful one.

Potent Elixirs

At 13th level, your expertise in brewing elixirs has reached new heights.  You gain the following effects:

1. Improved Healing - When you roll a 1 or 2 on a healing die, you can reroll the die and must use the new roll, even if the new roll is a 1 or a 2.
2. Expanded Antidote - The targeted creature can make an immediate saving throw with Advantage against any one poison, disease, or one of the following conditions temporarily affecting it:  blinded, charmed, deafened, frightened.  On a successful save, the poison, disease, or condition is removed from the target.
3. Enhanced Stimulant - The targeted creature can take the Dash, Dodge, or Disengage action on its next turn as a Bonus Action and its speed is increased by 10 feet for 1 minute.

Ultimate Alchemist

At 17th level, your skill in alchemy is unparalleled among mortals.  You gain the following effects:

1. Your bombs ignore resistance to their damage type.
2. Your healing elixirs provide half of the amount healed as temporary HP.
3. Your antidotes can now attempt to remove the following additional conditions:  paralyzed, petrified, and stunned.
4. The target of your stimulant gains resistance to nonmagical bludgeoning, piercing, and slashing damage for 1 minute.