Special Equipment. The assassin wields an oathbow and has 12 arrows of humanoid slaying in its quiver. It wears  studded leather +3 and gloves of thievery, carries a portable hole and bears a ring of free action, a ring of water walking and a ring of mind shielding.

Assassinate. The assassin has advantage on initiative rolls, and during its first turn, the assassin has advantage on attack rolls against any creature that hasn't taken a turn. Any hit the assassin scores against a surprised creature is a critical hit.

Child of the Crimson Order. The assassin can cast locate creature at will without material components to determine the location of the target assigned to it by the order. Furthermore, the assassin can call upon Bhaal's blessing to summon two magical daggers made of solidified gloom to its hands at any time.

Evasion. If the asssassin is subjected to an effect that allows it to make a Dexterity saving throw to take only half damage, it instead takes no damage if it succeeds on the saving throw, and only half damage if it fails. The assassin can't use this trait if it is incapacitated.

Legendary Resistance (3/day). If the assassin fails a saving throw, it can choose to succeed instead.

Mask of Shadows. While it is in darkness, the assassin is invisible. In addition, the assassin can hide even if it only is lightly obscured, and missing with a ranged attack does not reveal the assassin's location.

Sneak Attack (1/turn). Once per turn, the assassin deals an extra 42 (12d6) 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 the assassin that isn't incapacitated and the assassin doesn't have disadvantage on the attack roll.

Spellcasting. The assassin is an 8th level spellcaster. Its spellcasting ability is Intelligence (spell save DC 20, +12 to hit with spell attacks). It knows the following spells:

Cantrips (at will): guidance, mage hand, mold earth, prestidigitation, minor illusion

1st level (4 slots): absorb elements, detect magic, disguise self, hunter's mark, zephyr strike

2nd level (3 slots): hold person, invisibility, misty step, pass without trace, suggestion

3rd level (3 slots): counterspell, haste, major image, nondetection, sending

4th level (2 slots): death ward, dimension door, greater invisibility, shadow of moil

Superior Reflexes. Creatures provoke opportunity attacks from the assassin even if they take the disengage action before leaving its reach.

Multiattack. The assassin makes three attacks with its oathbow or four attacks with its daggers. It can replace one of these attacks with its Death Strike if available.

Crimson Blade. Melee Weapon Attack: +18 to hit, reach 5 ft., one target. Hit: 17 (1d4+15) piercing damage plus 21 (6d6) necrotic damage and the target cannot regain hit points until the end of its next turn. Furthermore, until the end of its next turn, if the target attempts to teleport or otherwise tries to use planar travel, it must first succeed on a DC 23 Charisma saving throw, or its attempt fails and the spell slot or use of the ability is wasted

Oathbow. Ranged Weapon Attack: +15 to hit, range 600 ft., one target. Hit: 12 (1d8+7) piercing damage. If the target is the assassin's sworn enemy, the attack has advantage and the target takes an additional 10 (3d6) piercing damage.

Oathbow (arrow of slaying). Ranged Weapon Attack: +15 to hit, range 600 ft., one target. Hit: 12 (1d8+7) piercing damage and the target must succeed on a DC 17 Constitution saving throw, taking 33 (6d10) piercing damage on a failed save or half as much on a success. If the target is the assassin's sworn enemy, the attack has advantage and the target takes an additional 10 (3d6) piercing damage.

Assassin's Maneuvers. Once per turn, when the assassin hits with a weapon attack, it  can channel Bhaal's dark magic to cause one of the following effects.

• Crimson Chains. Vicious, bladed chains wrap around the target, which takes an additional 14 (4d6) slashing damage and must make a DC 23 Strength saving throw or be restrained. The target or any creature that can reach it can use its action to remove the chains with a successful DC 23 Strength (Athletics) check, but takes 14 (4d6) slashing damage on a fail. Otherwise, the chains last for 1 minute or until the assassin uses that maneuver again.
• Night Slash. The darkness itself lashes out at the target. The target takes an additional 14 (4d6) necrotic damage and must make a DC 23 Constitution saving throw or be blinded and deafened for 1 minute. It can repeat the saving throw at the end of each of its turns, ending the effect on a success.
• Enfeebling Slash. The target hears Bhaal's whispers and is shaking in fear as it realizes its imminent fate. It takes an additional 14 (4d6) psychic damage and must make a DC 23 Wisdom saving throw or be frightened until the end of its next turn. While frightened in this way, it deals only half damage with its weapon attacks.
• Fatal Wound. The target takes an additional 14 (4d6) piercing damage and must make a DC 23 Constitution saving throw or suffers a bleeding wound. While wounded in this way, it takes 14 (4d6) necrotic damage at the start of each of its turns. Whenever the target is subjected to magical healing, it can repeat the saving throw. On a success, the wound closes and the effect ends for it.

Death Strike (Recharge 5–6). The assassin makes an attack with its daggers with advantage on the attack roll against a creature it has grappled. If the attack hits, the target must make a DC 23 Constitution saving throw. On a failure, it has its throat slit and dies instantly. On a success, it takes the attack's damage including Sneak Attack if applicable plus an additional 42 (12d6)  piercing damage and the grapple ends.

All creatures of the assassin's choice who are within 60 feet of the assassin and can see the attack must make a DC 23 Wisdom saving throw or be frightened until the end of their next turn.

Cunning Action. The assassin can take a bonus action on each of its turns to take the dash, disengage, hide or search action.

Crimson Blessing (3/day). As a bonus action, the assassin regains 30 hitpoints and ends the frightened condition on itself. In addition, until the end of the turn, the assassin's weapon attacks deal an additional 2d6 necrotic damage on a hit.

The assassin can take a total of three reactions per round, although only one per turn.

Uncanniest Dodge. The assassin adds 8 to its AC against one attack that would hit it. If the attack still hits, the assassin has resistance to the attack's damage.

Relentless Killer. When the assassin makes an opportunity attack, it can, as part of that reaction, move up to half its speed.

Skirmisher. When another creature ends its turn within 5 feet of the assassin, it can use its reaction to move up to half its speed. This movement does not provoke opportunity attacks.