Caspar, Master Assassin

Magic Resistance. Caspar has advantage on saving throws against spells and other magical effects.

Magic Weapons. Caspar's weapon attacks are magical.

Quick Reflexes. Caspar can take up to 3 reactions per round of combat, but only one per turn.

Silence of an Assassin. Caspar does not need verbal components of spells to cast them.

Innate Spellcasting. Caspar knows the spells alter self, misty step, and greater invisibility, and can cast them at will. 

Revealed! If an attack or spell damages Caspar whilst he is invisible, Caspar immediately becomes visible, and any effects that would cause him to be invisible cease.

Multiattack. Caspar makes three attacks. 

Dagger Strike. Melee Weapon Attack: +13 to hit, reach 5 ft., one target. Hit: 25 (4d8 + 7) slashing damage. The target must succeed on a DC 18 Constitution saving throw or become poisoned. While poisoned, the target takes 18 (4d8) poison damage at the start of each of its turns. The poisoned target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Go for the Eyes. Melee Weapon Attack: +13 to hit, reach 5 ft., one target. Hit: 25 (4d8 + 7) piercing damage. The target must succeed on a DC 18 Constitution saving throw or become blinded. The blinded target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Fan Daggers. Ranged Weapon Attack: +13 to hit, range 120 ft., up to three targets. Hit: 13 (1d8 + 7) slashing damage. 

Caspar can cast greater invisibility or misty step on his turn as a bonus action. 

Slip Away. When Caspar takes damage from an attack or spell, Caspar can teleport up to 40 ft. away and then cast greater invisibility on himself.

Retaliate. When an attack or spell misses Caspar, he can make a melee weapon attack against the assailant using his dagger if they are within 5ft. If not, he can instead make a ranged attack using one dagger from his "Fan Daggers" attack if they are within 120 ft. If this attack connects and deals damage to the target, the target must succeed on a DC 18 Constitution saving throw or be incapacitated until the end of its turn.