Astar, Collector of Debts

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

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

Sneak Attack. Once per turn, Astar deals an extra 27 (6d8) 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 Astar that isn't incapacitated and Astar doesn't have disadvantage on the attack roll.

Spawn of Glasya. A descendent of Hell's criminal mastermind, Glasya, Astar can cast minor illusion at will, disguise self (1/day), and invisibility (1/day) using Charisma as his spellcasting ability for these spells. He is also resistant to psychic damage.

Multiattack. Astar can take the hide action and makes two attacks with the Nine Lives Stealer.

Nine Lives Stealer (9 charges). Melee Weapon Attack: +7 to hit, range 5 ft., one target. Hit: 8 (1d8 +2) slashing damage. If Astar critically-hits a target with 100 hit points or fewer, it must make a DC 15 saving throw or be slain instantly as the sword tears its life force from its body (a construct or an undead is immune). The sword loses 1 charge if the creature is slain. When the sword has no charges remaining, it loses this property.

Light Crossbow. Ranged Weapon Attack: +9 to hit, range 80/320 ft., one target. Hit: 7 (1d8 + 3) piercing damage, and the target must make a DC 18 Constitution saving throw, taking 24 (7d6) poison damage on a failed save, or half as much damage on a successful one.