Hitman

In your life you never were much of a fan this whole "law" thingy. Only LAW that hold actual real power is strength. Weak will always get bullied by stronger, that's just how it is and you vowed to yourself that you will be within strong ones. Even if faced by stronger, more agile or magically gifted you have keen eye for weakness to exploit. Your working for underground syndicate taught you how to deal with high variety of opponents. You found great appreciation for short weapons which are easy to hide because even strong opponent can be dealt with relatively easily if taken by surprise or with well aimed attack. 

Eye For Weakness

3rd-level Hitman feature

Starting at 3rd level you can use your bonus action to to start observing enemy within 5 feet of you and you have to stay within that distance until end of your turn. At the start of your next turn make an Insight (WIS) ability check against enemy's AC. On success you were able to spot weak point in his defense granting you advantage against him until end of your turn. Additionally your sneak attack die number is increased by number equal to your proficiency bonus as long as you attack that opponent. On a failed check nothing happens and you can not use this ability on same target until next turn. 

From the Shadow

3rd-level Hitman feature

Killing is always much more easy if done unexpected. You gain proficiency in the Stealth skill if you don't already have it. Your proficiency bonus is doubled for any ability check you make that uses this proficiency.

Technique over Length

9th-level Hitman feature

This not length that makes a man, it's his technique. And there is no better weapon to express your finesse than daggers. People see their short range and unimpressive size as weakness, but you know better than them. This elegant weapon can be easily squeezed between armor plates and when fighting chest to chest long reach of most weapons becomes their shortcoming. When wielding a dagger you are able to score critical hit on rolls of 19 or higher. Additionally after scoring critical hit with a dagger you can triple your sneak attack die number instead of doubling. You can use this special effect number of times equal to your proficiency bonus for long rest. 

Maim their Strength

13th-level Hitman feature

Some enemies over-rely on their strong sides, sometimes disturbing their advantage is more destructive than aiming for weakness.  As an action you can make special melee weapon attack against enemy under effect of your Eye For Weakness feature but instead gaining advantage and additional damage from sneak attack you impose one of the following effect depending on enemy's higher physical Ability Score. This effect takes effect after attack and last 1 minute. 

• Strength - Any grapple/restrain they attempt has advantage to be defended against. Additionally their melee attacks can not deal more damage than average for this attack action (if damage rolled exceeds that average number it is brought down to it)
• Dexterity - Their movement speed is decreased by 15 ft. (but can not be decreased bellow 5 ft.). Additionally their sluggish movement decrease their AC by 2.
• Constitution - They lose ability to regain hit points. Additionally they lose any damage resistances and saving throws to maintain concentration are made with disadvantage. 

You can use this action once per short rest and it is not used unless it lands successfully. 

Make it Quick

17th-level Hitman feature

The longer fight is taking the worse outcome may be. You trained yourself to make sure you are most deadly early on in combat and deliver quick end. For the first round of combat you gain following benefits:

• You gain +20 bonus to your initiative.
• You can not be surprised.
• Your attack auto-crit on hit.
• You passively gain benefits of Disengage, Dodge and Dash actions. 
• All enemies are under effect of your Eye For Weakness feature.

All these effects end at the end of First round.