Marauder

Marauders can deceive and steal all sorts of things. They can trick others with their eloquence, sleight-of-hand and even steal their targets abilities, thoughts, intentions and life.

Level 3: Superior Observation

You can sense if there is something valuable in a drawer, cupboard or chest, within 30feet of you, without actually being capable of seeing what's inside.

With this sense you cannot tell what the item looks like or other things about the item, other than it's approximate value.

Level 3: Theft

You have a exceptional ability to steal things, you gain expertise in sleight of hand.

As a action you can attempt to steal a specific ability or object from a target within 15 feet or give the target an object without them noticing, make a contested d20 + proficiency roll against the targets wisdom(perception), if you succeed the targets ability gets temporarily transferred to you. If the target is in combat with you or can see you perform the theft then you have disadvantage and the target has advantage on the roll. You have access to that ability for 1 minute or until you use it once, then it returns to the target.

Abilities are things both mundane (like the ability to walk, fly or speak) or special (like a bards ability to grant bardic inspiration).

Once you reach 9th level you can use theft as a bonus action instead of an action and it's range improves to 30ft.
Once you reach 17th level you can add your double your proficiency Bonus to the roll and it's range improves to 60ft.

You can use this feature a number of times up to your proficiency modifier.

Level 9: Dream Stealer

You can use Theft to directly steal a Targets thoughts.

When you use Theft you now can target thoughts, and on a successful theft the Target gains the Stunned condition until the end of you next turn and you learn what the Target wanted to do during that time.

Level 13: Mentor of Deceit

When you use Theft you can now steal the distance between a Target you can see and yourself, using 5ft of your movement you can appear next to the Target. You still provoke opportunity attacks.

Level 17: Parasite

You have become extremely adept at Stealing, able to steal Life itself.
When you deal sneak attack damage, you now also decrease the Targets maximum hit points until they take a long rest.

Additionally if your sneak attack damage kills a sentient living creature (non-undead, non-construct, with an intelligence score above 8) it quickly withers away and your life expectancy increases by 1 year.