Level 3
Low Blow.
When you Sneak Attack, you may spend 2 additional actions to Incapacitate your target for their next turn on a failed STR save (DC 10+INT). Save or fail, they are Taunted by you until you drop to 0 HP.
Sweet Talk.
You may gain advantage on all Influence checks with NPCs you've just met for the first time. This lasts until you fail an Influence check with them or until you meet a 2nd time. You have disadvantage on Influence checks with them after you use this ability (until you get back on their good side).
Level 7
Pocket Sand.
(2/encounter—you've got to collect more sand!) When you Defend against a melee attack, Blind the attacker until the start of their next turn and force them to reroll the attack (Blinded creatures attack with disadvantage).
Level 11
Escape Plan.
(1/Safe Rest) When you would drop to 0 HP or gain a Wound, you don't. Instead, you turn Invisible for 1 minute or until you attack.
Level 15
Heads I Win, Tails You Lose.
(1/encounter) Attacks you make this round don't miss, you crit on 1 less than normally needed, and you gain LVL temp HP.