One ability score of your choice increases by 2, and one increases by 1.

Humans reach adulthood in their late teens and live less than a century.

Humans vary widely in height and build, from barely 5 feet to well over 6 feet tall. Regardless of your position in that range, your size is Medium.

Your base walking speed is 30 feet.

Creatures in this world are permeated with magic from the moment of their conception to the day of their death, and their bodies adapt accordingly, even if they never learn to harness it themselves. You have no such privilege. You have disadvantage on all saving throws against spells and magical effects.

You can speak, read, and write two languages of your choice. Common is not strictly one of them.

Whether able to shrug off or rapidly heal countless mortal wounds through the use of a gleaming magical aura, or be it simple obscene luck, the heroes of this world are preternaturally hardy. You have no such power, and a single well placed arrow would kill you just as surely as any common farmhand.

Instead, you carry a device that projects an energetic field around you, deflecting all harm. This device cannot be removed from you against your will as long as you are alive, as it is held to you by its own force-field.

Your maximum hitpoints are reduced to one fourth your level, times your Constitution Modifier (Minimum of 4 Hit Points). When you finish a Short or Long Rest, you gain Temporary Hit Points equal to your level times the average value of your largest Hit Die. While you have these Temporary Hit Points, you have resistance to Force damage. At the start of your turn, if you have not taken damage since the start of your last turn, you may use your action to spend and roll any number of remaining Hit Dice and increase your current Temporary Hit Points total by the amount rolled + your Constitution or Intelligence modifier per die spent.
Once when the Mending cantrip is cast on you, you may immediately reset your Temporary Hit Points as if you had just finished a Rest. You regain the ability to benefit from Mending in this way when you finish a Short or Long Rest.

If you do not spend any Hit Dice to recover Hit Points during a Short Rest, you may recover a number of Hit Dice equal to your Proficiency Modifier (but no more than half your level).

Any spells you know from class features are considered nonmagical effects when you cast them and do not count as spells for the purposes of disruptive effects like Counterspell or Dispel Magic. You are proficient with Tinkers Tools, and may always use them or a firearm (if you are proficient) as a spellcasting focus.