When you attack while hidden, and the attack misses, you are not revealed. Additionally, once per turn, when you make a weapon attack while hidden, you can deal additional damage equal to your proficiency bonus.

You gain proficiency in Stealth or Acrobatics.

Martial Training: You gain proficiency with Medium Armor and Martial Weapons. Additionally, you learn one Battle Master Maneuver and gain a d4 superiority dice. The saving throw DC equals 8 + your proficiency bonus + your Strength or Dexterity modifier (your choice).You can use this maneuver a number of times equal to your proficiency bonus, and you regain all expended uses when you finish a long rest.

You gain proficiency in Athletics or Intimidation.

As an action, you touch a creature and temporarily warp its flesh for 1 minute. It gains a Slam attack as a bonus action, dealing 1d6 bludgeoning damage, increasing to 1d8 at 5th level, and 1d10 at 11th level. Alternatively, the mutation can reduce its speed by 5ft and cause a penalty to its attack rolls equal to half your proficiency bonus rounded down. You can use this trait a number of times equal to your proficiency bonus, and you regain all expended uses when you finish a long rest.

You gain proficiency in Arcana or Medicine.

You have advantage on saving throws against disease and cannot be poisoned. Additionally, you have resistance to poison damage.

As a bonus action, you emanate a 5-foot radius aura of disease that lasts for 1 minute. You can choose which creatures are affected by this effect. Any creature that starts its turn within the aura or enters it for the first time on a turn must make a DC 10 + your proficiency bonus Constitution saving throw. On a fail, a creature takes poison damage equal to your proficiency bonus and is diseased. While diseased, a creature has disadvantage on attack rolls and ability checks, and takes poison damage at the end of its turn equal to half your proficiency bonus (rounded down). A diseased creature emits a 5-foot radius aura functioning as your Plague Aura, affecting any of the creatures you initially targeted.

At the start of each of its turns, the creature can make another Constitution saving throw. On a success it ignores the effects of the disease for that turn. 
All effects end when your Plague Aura ends. You can use this ability a number of times equal to your proficiency bonus, and you regain all expended uses when you finish a long rest.

You gain proficiency with the Poisoner's Kit or Alchemy Supplies.

You learn Shocking Grasp and Guiding Bolt. You can cast Guiding Bolt without spending a spell slot twice with this trait and regain the ability to do so when you finish a long rest. Intelligence is your spellcasting ability for these spells.

As an action, you can choose to regain one spell slot of a level you have spell slots available for, or one usage of a class feature or ability that refreshes after a long rest. Once you use this feature, you must finish a long rest before you can use it again. Starting at 10th level, you can use this feature twice, and a third time at 17th level.

You gain proficiency with Tinker's Tools or Investigation. Additionally, you can ignore the loading property of weapons.