Mastermind

Mastermind rogues are cunning strategists, equipped with a wit and tongue as sharp as the weapons they carry. These rogues mould themselves to better influence people or pry into secrets they hold, and excel at deducing the weaknesses of their targets. Masterminds have a sharp eye for detail which allows them to unravel mysteries and exploit the weaknesses of their targets. 

Craft of Parlance

When you choose this archetype at 3rd level, you train yourself in a versatile array of talents for social situations. You gain proficiency with the disguise kit, the forgery kit, and one gaming set of your choice. You also learn two languages of your choice. 

Additionally, you can unerringly mimic the speech patterns and accent of a creature that you hear speak for at least 1 minute, enabling you to pass yourself off as a native speaker of a particular land, provided that you know the language.

Deciphered Foe

Beginning at 3rd level, you gain the ability to decipher an opponent’s tactics and develop counters to them. As a bonus action, you can choose one target you can see and visually decipher them. You have advantage on all checks made in combat to learn information about the deciphered creature, and you don’t need advantage on your attack roll to use Sneak Attack against the target creature if you don’t have disadvantage on the attack roll. All the other rules for Sneak Attack still apply to you.

This benefit lasts for 1 minute or until you use this feature against a different target.

Candied Words

Starting at 3rd level, you can say sweetened words that sways your attackers. When you perform an Uncanny Dodge, as a part of your uncanny dodge, you can force the attacking creature to make a Wisdom saving throw (DC equal to 8 + your proficiency bonus + your Dexterity modifier). On a failed save, the attacking creature becomes charmed by you until the end of your next turn.

Artful Socialite

Beginning at 6th level, you gain a hint of eloquence that improves your speech. When you make a Charisma (Persuasion) or Charisma (Deception) check, you can choose to reroll the d20. You must choose to reroll this die before the DM determines whether the result of the skill check, and you must take the new roll.

You can use this feature a number of times equal to your Charisma modifier (minimum of once), and regain all expended uses after completing a long rest. 

Steadied Aim

Starting at 6th level, your intuition grants you the ability to strike where it hurts most. You gain a pool of d6s equal to your number of Sneak Attack dice. 

Whenever you deal damage with your Sneak Attack feature, you can spend dice from your pool of d6s to add additional damage to the attack. You choose the number of dice to spend from the pool, roll the dice, and add the results to the damage you deal. The maximum number of dice you can spend at once in this way equals half your Dexterity modifier (rounded up).

Your pool regains all expended dice when you finish a long rest. You can also expend one use of your Cunning Tactics to regain all expended dice in your pool; after you regain your expended dice with your Cunning Tactics, you must complete a long rest before you can regain dice in this way again.

Unerring Eye

Beginning at 11th level, your senses are almost impossible to foil. You sense the presence of illusions, shapechangers not in their original form, and other magic designed to deceive the senses within 20 feet of you, provided you aren't blinded. You sense that an effect is attempting to trick you, but you gain no insight into what is hidden or into its true nature.

Eye for Detail

Starting at 11th level, you learn to exploit a creature's weaknesses by carefully studying its tactics and movement. Whenever you perform a Shady Scheme that forces the target to make a saving throw, you can expend three dice from your d6 pool granted by your Steadied Aim feature to apply a 1d6 penalty to the target’s saving throw.

Additionally, when a creature you’re deciphering in combat dies, you can immediately decipher another creature you can see with no action required. 

Tactical Foresight

Beginning at 17th level, your intuitive mind allows you to predict your enemy’s moves. You can now decipher two creatures at a time, and you can decipher multiple creatures with the same bonus action. Creatures who you decipher also have disadvantage on attack rolls against you, and you have advantage on any effects a deciphered creature uses on you that forces you to make a saving throw.