Artoria Nelgoff (The Whistling Blade)

Musical Spellcasting. Artoria Nelgoff is a 6th-level spellcaster. Her spellcasting ability is Charisma (spell save DC 16, +8 to hit with spell attacks). It can cast the following spells , and can cast without material components by playing her Shamisen.

Cantrips (at will): minor illusion, viscous mockery

1st level (4 slots): dissonant whispers, healing word, heroism, sleep, thunderwave, silent image

2nd level (3 slots): aid, enhance ability, silence

3rd level (2 slots): bestow curse, fireball, haste

Assassinate. During her first turn, Artoria has advantage on attack rolls against any creature that hasn't taken a turn. Any hit Artoria scores against a surprised creature is a critical hit.

Evasion. If Artoria is subjected to an effect that allows her to make a Dexterity saving throw to take only half damage, Artoria instead takes no damage if she succeeds on the saving throw, and only half damage if it fails.

Sneak Attack. Once per turn, Artoria deals an extra 17 (5d6) damage when it hits a target with a weapon attack and has advantage on the attack roll, or when the target is within 5 feet of an ally of Artoria that isn't incapacitated and Artoria doesn't have disadvantage on the attack roll.

Dark Draw. When you draw this weapon and make an attack with it as part of the Attack action on the same turn, you can replace the first attack you make with it with a special strike. When you do, the sword swings out in a devastating arc, which extends from you in a 15-foot cone of wicked shadow. Make a melee attack with the sword against each creature within the area, with a separate attack roll for each target: on a hit, a target takes an extra 1d6 necrotic damage from the attack. If any of the sword's d6 damage dice roll a 6, the target must also succeed on a DC 16 Constitution saving throw or be blinded until the start of your next turn. Once this property of the sword has been used, it can't be used again until 1 minute has passed.

Blade Symbol: The warrior has chosen you to bear its blade, with you gaining the following benefits:
Severed Knowledge. You instantly identify any melee weapon you touch.
Sharpened Style. For 1 minute your melee weapon gains the magic property, dealing an additional 1d6 damage of that melee weapon’s type.
Familiar Duel. After a long rest you mark a melee weapon and until you die or pass it to another weapon you can will it to your hand no matter the distance.

Multiattack. Artoria makes two attacks with Shadowcutter.

Shadowcutter (Greatsword). Melee Weapon Attack: +11 to hit, reach 5 ft., one target. Hit: 14 (2d6 + 7) slashing damage. 

Light Crossbow. Ranged Weapon Attack: +8 to hit, range 80/320 ft., one target. Hit: 9 (1d8 + 5) piercing damage, and the target must make a DC 15 Constitution saving throw, taking 24 (7d6) poison damage on a failed save, or half as much damage on a successful one.

Bardic Inspiration (4/Short or Long Rest). The bard chooses a creature other than itself that is within 60 feet of it and can hear it. The bard grants this creature an Inspiration die that lasts for 10 minutes. The creature can expend this die to add 1d8 to an ability check, attack roll, or saving throw. Once the die is used or expires, it is lost. A creature can only benefit from one Inspiration die at a time.

Cutting Words. When a hostile creature makes an attack roll, ability check, or damage roll, the bard can use its reaction to expend one use of its Bardic Inspiration, rolling the Inspiration die and subtracting the number rolled from the creature's roll. The creature is immune if it can't hear the bard or is immune to being charmed.