Special Equipment. Sil wields a pair of vicious daggers and an oathbow, and carries a quiver of ehlonna with 12 arrows of humanoid slaying and 20 arrows +3. He wears boots of elvenkind, a cape of the mountebank and studded leather +3, carries a handy haversack and a portable hole and bears a ring of free action, a ring of water walking and a ghost step tattoo.

He will also drink a potion of heroism while hidden before he attempts to assassinate a target he knows might be more difficult to kill and might have some potent injury poisons applied to his arrows. He also might have other potions, such as a potion of healing (greater), availabe determined by the DM.

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

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

Indomitable (3/day). If Sil fails a saving throw, he can choose to succeed instead.

Mask of Shadows. While he is in darkness, Sil is invisible to any creature that relies on darkvision to see him in that darkness. In addition, Sil can hide even if he only is lightly obscured, and missing with a ranged attack does not reveal his location.

Multiattack Defense. When Sil is attacked by a creature, he gains a +4 bonus to his AC against all further attacks made by that creature on this turn.

Sneak Attack (1/turn). Once per turn, Sil deals an extra 35 (10d6) damage when he 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 Sil that isn't incapacitated and Sil doesn't have disadvantage on the attack roll.

Spellcasting. Sil is a 6th level spellcaster. His spellcasting ability is intelligence (spell save DC 21, +12 to hit with spell attacks). He 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, hail of thorns, hunter's mark, longstrider, zephyr strike

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

3rd level (3 slots): counterspell, flame arrows, haste, lightning arrow, major image, nondetection, sending

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

Multiattack. Sil makes three attacks with his Oathbow or four attacks with his daggers. He can also replace one of these attacks with his Death Strike if available.

Vicious Dagger. Melee Weapon Attack: +14 to hit, reach 5 ft., one target. Hit: 10 (1d4+7) piercing damage and the target must make a DC 21 constitution saving throw, taking 28 (8d6) poison damage on a failure or half as much on a success.

Oathbow (+3 arrrow). Ranged Weapon Attack: +17 to hit, range 600 ft., one target. Hit: 15 (1d8+10) piercing damage. If the target is Sil's sworn enemy, the attack has advantage and the target takes an additional 10 (3d6) piercing damage.

Oathbow (arrow of slaying). Ranged Weapon Attack: +14 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 Sil's sworn enemy, the attack has advantage and the target takes an additional 10 (3d6) piercing damage.

Maneuvers. Once per turn, when Sil hits with a weapon attack, he can choose to perform one of the following maneuvers:.

• Death Curse. Sil whispers words of dread. The target takes an additional 14 (4d6) necrotic damage and must make a DC 21 wisdom saving throw. On a failure it is cursed for one minute. While cursed, it takes 14 (4d6) necrotic damage at the start of each of its turns and can't regain hit points. It can repeat the saving throw at the end of each of its turns, ending the effect on a success. Otherwise the curse lasts for 1 minute or until Sil uses this maneuver again.
• Iron Chains. Vicious, bladed chains wrap around the target, which takes an additional 14 (4d6) slashing damage and must make a DC 21 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 21 strength (Athletics) check, but takes 14 (4d6) slashing damage on a fail. Otherwise, the chains last for 1 minute or until Sil uses that maneuver again.
• Overwhelm. Sil attempts to overwhelm his target to get into position for the deadly strike. The target takes an additional 14 (4d6) bludgeoning damage and must make a DC 21 strength saving throw. On a failure, it is knocked prone and Sil can use a bonus action to attempt to grapple it.
• Shadow Lash. The darkness itself lashes out at the target. The target takes an additional 14 (4d6) necrotic damage and must make a DC 21 constitution saving throw or is blinded for 1 minute. It can repeat the saving throw at the end of each of its turns, ending the effect on a success.
• Spellbreaker. A wave of antimagic washes over the target, which takes an additional 14 (4d6) force damage and must succeed on a DC 21 intelligence saving throw or be affected by dispel magic as if it was cast at 3rd level.

Death Strike (recharge 5, 6). Sil makes an attack with his daggers with advantage on the attack roll against a creature he has grappled. If the attack hits, the target must make a DC 21 constitution saving throw with disadvantage. 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 35 (10d6)  piercing damage and the grapple ends.

All creatures of Sil's choice who are within 60 feet of him and can see the attack must make a DC 21 wisdom saving throw or be frightened until the end of their next turn.

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

Ghost Step (3/day). Sil can use a bonus action to become incorporial until the end of his next turn. In this state he has resistance to bludgeoning, piercing and slashing damage from nonmagical attacks, cannot be grappled or restrained and can move through creatures and solid objects as if they were difficult terrain; however, if he ends his turn within a solid object, he takes 1d10 force damage and is shunted to the nearest unoccupied space.

Second Wind (3/day). As a bonus action, Sil regains 30 hitpoints.

Uncanny Dodge. When Sil gets hit by an attack, he can use his reaction to halve the attack's damage.

Relentless Killer. When Sil makes an opportunity attack, he can, as part of that reaction, move up to half his speed.

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