Nisril can take the Attack action three times instead of once whenever she takes the Attack action on her turn.

As a Bonus Action, regain 1d10 + 12 Hit Points. Nisril has four uses, regaining one use on a Short Rest and all uses on a Long Rest.

Whenever Nisril uses Second Wind as a Bonus Action, she can move up to half her Speed without provoking Opportunity Attacks.

Nisril gains one feat of her choice. She selected Observant, gaining proficiency in Investigation if not already proficient, the ability to search as a Bonus Action, and a +5 bonus to her Passive Perception and Passive Investigation.

Nisril can cast Shield as a Reaction when hit by an attack, gaining a +5 bonus to AC until the start of her next turn, potentially causing the attack to miss. Usable once per Long Rest without a spell slot.

Nisril gains one feat of her choice. She selected Mage Slayer, gaining Advantage on saving throws caused by creatures within 5 feet and the ability to make a weapon attack as a Reaction when a nearby creature uses a spell.

When a creature misses Nisril with a melee attack, she can use her Reaction and expend one Superiority Die to make a melee weapon attack, adding the die to the damage on a hit.

When Nisril hits with a weapon attack, she can expend one Superiority Die to add it to the damage and force the target to make a Strength saving throw or drop one object it is holding.

When Nisril hits a creature, she can expend one Superiority Die to add it to the damage and grant the next attack against that creature Advantage.

When Nisril hits with a weapon attack, she can expend one Superiority Die to add it to the damage and force a Wisdom saving throw or cause the target to have the Frightened condition until the end of Nisril's next turn.

Nisril can expend one Superiority Die after making an attack roll but before knowing whether it hits, adding the die to the roll.

When Nisril hits a creature with a weapon attack, she can expend one Superiority Die to add it to the damage and force the target to make a Strength saving throw or be pushed up to 15 feet.

When Nisril hits a creature with a weapon attack, she can expend one Superiority Die to add it to the damage and force the target to make a Strength saving throw or fall Prone.

Nisril can expend one Superiority Die and add it to an Intelligence, Wisdom, or Charisma ability check. She can also gain proficiency with History, Investigation, or Persuasion for that check if she lacks it.

You gain a Fighting Style feat. Nisril has Defense, granting a +1 bonus to AC while wearing armor.

Nisril can use the mastery properties of five Simple or Martial weapons. Her prepared mastery weapons are quarterstaff, longsword, maul, javelin, and longbow.

Nisril can take one additional action on her turn, except the Magic action. Usable once per Short or Long Rest.

When she fails an ability check, Nisril can expend a Second Wind use to add 1d10 to the check. If the check still fails, the use is not expended.

Nisril gains the Battle Master subclass, learning combat maneuvers fueled by Superiority Dice.

Nisril gains one feat of her choice. She selected Alert, granting a +5 bonus to Initiative, immunity to being Surprised while conscious, and the ability to swap Initiative with a willing ally at the start of combat.

Nisril gains one feat of her choice. She selected Skilled, gaining proficiency in Persuasion, Religion, and Survival.

Nisril gains Student of War, proficiency with Calligrapher's Supplies, and learns two additional Battle Master maneuvers.

Nisril can reroll a failed saving throw and add her Fighter level to the roll. Usable once per Long Rest.

When attacking with a weapon whose mastery property she can use, Nisril can replace that property's effect with Push, Sap, or Slow for that attack.

Nisril's Superiority Dice become d10s. She knows eight maneuvers and has four Superiority Dice, regained on a Short or Long Rest. Her maneuvers are Commander's Strike, Disarming Attack, Distracting Strike, Menacing Attack, Precision Attack, Riposte, Sweeping Attack, and Tactical Assessment.

Magic Initiate (Wizard). Nisril knows the Light and Message cantrips and can cast Shield once per Long Rest without a spell slot. Intelligence is her spellcasting ability for these spells.