You can use a Bonus Action to Dash, Disengage, or Hide.

You can take the Utilize action, or use a magic item requiring the Magic action, as a Bonus Action.

Fast Hands lets you take the Utilize action, or take the Magic action to use a magic item that requires that action, as a Bonus Action. Second-Story Work grants a Climb Speed equal to your Speed and lets you add your Dexterity modifier to the distance of your running jumps.

When an attacker hits you, use your Reaction to halve the attack's damage against you.

Swap initiative with a willing ally in the same combat immediately after rolling initiative, provided neither creature is Incapacitated.

After hitting with an attack that qualifies for Sneak Attack, expend 1d6 from the Sneak Attack damage to force the target to drop one object it is holding. The target makes a Dexterity saving throw against DC 14.

After hitting with an attack that qualifies for Sneak Attack, expend 1d6 from the Sneak Attack damage to apply poison to the wound. The target makes a Constitution saving throw against DC 14 or has the Poisoned condition until the end of your next turn.

After hitting with an attack that qualifies for Sneak Attack, expend 1d6 from the Sneak Attack damage to knock the target Prone if it fails a Strength or Dexterity saving throw against DC 14.

You gain Expertise in two proficient skills or tools. Choose Stealth and Thieves' Tools. Your proficiency bonus is doubled for ability checks using them.

Once per turn, you can deal an extra 2d6 damage to a creature you hit with an attack if you have Advantage on the attack roll and the attack uses a Finesse or Ranged weapon. You do not need Advantage if another enemy of the target is within 5 feet of it, that enemy is not Incapacitated, and you do not have Disadvantage.

You know the secret language of rogues and criminals, including hidden signs and coded expressions.

You gain mastery with four weapons. Mirei has mastery with the Dagger, Shortbow, Shortsword, and Rapier.

Mirei is a Thief. She gains Fast Hands and Second-Story Work.

You gain the Ability Score Improvement feat or another feat for which you qualify. Mirei's fixed ability scores remain as provided.

When you deal Sneak Attack damage, you can apply one Cunning Strike option by expending 1d6 from the Sneak Attack damage. Mirei knows Disarm, Poison, and Trip.

You gain Expertise in two more proficient skills or tools. Choose Investigation and Perception.

When you are subjected to an effect that allows you to make a Dexterity saving throw to take only half damage, you instead take no damage on a successful save and half damage on a failed save.

Whenever you make an ability check that uses one of your skill or tool proficiencies, you can treat a d20 roll of 9 or lower as a 10.

You have a reliable contact who acts as your liaison to a network of criminals. You know how to get messages to and from this contact, even across considerable distances, though the contact cannot guarantee assistance.