The art of combat in the modern age has changed. Firearms are widespread, magic is as much technological as it is arcane, and information is as deadly as a knife in the back. You, however, ignore all that. You are a bastion of pure, unstoppable might, powered by a cocktail of chemicals that would be lethal for pretty much any other creature. Picking and choosing which chemicals you want to use in any one moment allows you to respond to the battle as you see fit, keeping you at pace with the spells and bullets of modern combat.

Biomechanical Augmentation

Starting at 3rd level, you have wired yourself to an injection system that will pump you full of chemical cocktails when you need it most. You can activate the injection system as a bonus action, choosing from the following chemicals:

• Ability Enhancement. Choose one ability score. For the next minute, you have have advantage on checks with that ability score, and you gain proficiency in saving throws with that ability score if you didn’t have it already.

• Focused Sight. For the next hour, you have proficiency in Perception if you didn’t have it already, your proficiency bonus is doubled for checks you make with that proficiency, and you can see through lightly obscured spaces as if they were not obscured.

• Muscle Strengthener. For the next hour, your walking speed increases by 10 feet, your carrying capacity doubles, and you can attempt to grapple creatures that are two sizes larger than you.

• Skin Hardening. For the next minute, you gain a +1 bonus to your AC.

You can use this feature a number of times equal to your proficiency bonus, and you regain uses when you finish a long rest. You can only safely have one chemical active at a time. If you use this feature while you already have a chemical active, the second chemical takes effect, but you suffer one level of exhaustion. However, if the second chemical you activate is the same as the first chemical that was already active, the first instance ends, and you don’t suffer a level of exhaustion.

Tinkerer's Proficiency

Also at 3rd level, you have spent a lot of time tinkering with your injection system. You have proficiency with alchemist’s supplies and tinker’s tools.

Reactive Healing

Starting at 7th level, you gain another use of your Second Wind feature. In addition, when you take damage, you can use your reaction to use your Second Wind.

Power-Up Cocktails

At 10th level, you gain the following additional chemical options for your injection system:

• Limit Breaker. For the next minute, whenever you take the Attack action, you can make an additional weapon attack as a bonus action.

• Reflex Booster. For the next minute, when you make an opportunity attack, you can choose not to expend your reaction. You can use this feature once per round.

• Specialised Aenesthetic. For the next minute, you gain resistance to one damage type of your choice.

In addition, you can now have two chemicals safely active at once.

Adrenaline Surge

Starting at 15th level, your body is so used to and suffused by these chemicals that it starts to produce it along with adrenaline. When you use your Action Surge, you can activate your injection system as part of the additional action, without expending a use. You can do so before or after the additional action.

Biochemical Flood

By 18th level, you have rewired your injection system to allow you to overwhelm your system with chemicals as a last ditch effort. As an action, you can choose to inject up to three chemicals at once. All three chemicals last for 1 minute, regardless of their normal duration. Doing so only expends one use of your injection system. Once you use this feature, you can’t do so until you finish a long rest.