Residual Serum

Most potions have short-term effect, and leave no adverse lasting effects, but not all. Perhaps your ancestors used potions excessively, having some effects that were not just permanent, but heritable. Perhaps you have no such lineage but you received magical modifications to your body earlier in your life. Whatever your origin, your body now produces small amounts of some fantastical substances on its own.

When looking for a specialization, something you're good at, the awakening of the serums within you was a convenient answer. You chose to use them, rather than suppressing them. Amplify them, wield them. The serums offer great power, but it may come at the cost of your wellbeing.

Neutral Skill Checks

Some features in this subclass ask for a neutral skill check. This is a d20 roll that is not associated with any ability score or skill, but still counts as an ability check and a skill check.

Long Rest Recoil

Some features in this subclass trigger a recoil effect at the end of a long rest. This happens after the healing of the long rest, but before you wake up, or whatever the equivalent of waking up is for you.

Analysis Serum

Connecting your mind and your senses, one of the serums inside you allows you to quickly determine to composition and properties of certain substances.

Starting at 3rd level, you can use an action to identify a potion by tasting it or touching it. This uses an insignificant volume of liquid.

You can also quickly detect poisons and reflexively move to avoid them, or at least minimize their effects. As long as you can move, you can avoid ingestion poisons entirely, and you have advantage on saving throws against all poisons.

Focus Serum

Starting at 3rd level, you can use one of your serums to focus your attention beyond normal limits, picking the locks on others' hearts while lowering your own guard.

As an action, you can activate or deactivate this feature. While active, you have advantage on all Charisma ability checks and disadvantage on all Wisdom ability checks, and Charisma ability checks against you have advantage. You cannot rest (take short or long rests) while it is active.

Due to your unrefined control, once you activate this feature, you cannot deactivate it for 1 minute; likewise, after deactivating it, you cannot activate it again for 1 minute.

At the end of a long rest, if you have activated this feature since the end of your previous long rest, make a neutral skill check (DC 8). On a fail, you are tormented by bad dreams of being exploited and betrayed, causing you to take 1d6 psychic damage.

Restoration Serum

Starting at 9th level, a serum that can restore you to a state of better health becomes active.

As an action, you can kick the serum into overdrive to remove one negative status effect from yourself. For status effects that stack, such as exhaustion, it only removes 1 stack. This works on curses, charms, poisons, and various other effects.

You can use this feature a number of times equal to your Dexterity modifier. You regain all uses when you complete a long rest.

The restoration serum is imperfect, and the aggressive restoration sometimes over-heals you, leaving lasting damage. At the end of a long rest, for each time you used this feature since the end of your previous long rest, make a neutral skill check (DC 10). On a fail, you take 1d6 necrotic damage and your hit point maximum is permanently reduced by 1. This feature cannot undo its own hit point maximum reduction, but other effects like Greater Restoration can.

Warp Serum

At 13th level, you learn to harness a space-warping serum to teleport.

You gain 1000 feet of teleportation movement, which is also your maximum teleportation movement. You can use some of your teleportation movement as part of your movement, teleporting to a location. This could be specified by a location you can see, a location you know, or by direction and distance. If the location is out of range, the teleportation fails harmlessly, wasting all your remaining teleportation movement. If the location is occupied, the teleportation fails harmlessly, wasting however much movement you would have used to get there.

Teleportation movement does not refresh every turn like other movement. You regain 200 feet of teleportation movement upon finishing a short rest, up to your maximum. You regain all 1000 feet upon finishing a long rest.

Tip: While teleporting does not automatically give you advantage on attacks, you can use it to gain surprise or attack from a hidden location.

At the end of a long rest, make a neutral skill check (DC 15). On a fail, the warp serum activates uncontrollably, causing your rest to be troubled. You end up in an unoccupied space up to 15 feet away in a random direction from where you began your long rest. The maximum accidental teleport distance increases by 5 feet for every 25 feet of teleportation movement restored by the long rest.

Reversal Serum

At 17th level, you learn to combine your existing serums to produce a powerful new effect that momentarily reverses the laws of nature.

As an action, you can trigger the reaction of the serums, unleashing a wave of energy. All creatures within 30 feet of you including yourself have their immunities converted to vulnerabilities until the start of your next turn. Once you use this feature, you cannot use it again until you finish a long rest.

At the end of a long rest, if you used this feature since your previous long rest, make a neutral skill check (DC 20). On a fail, your body is ravaged by the byproducts of the reversal serum, causing you to take (100 * the modified roll) force damage, bypassing resistance and immunity. If you chose to fail this roll, the roll is treated as a 10.

Variant Recoil. If you use the rule that an unmodified roll of 20 on an ability check automatically succeeds, the DC to avoid recoil is increased to 22. This is for balance reasons.