Blood Knight

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

Sneak attack.  Once per turn, the Blood Knight deals and 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 the Blood Knight that isn't incapacitated and the Blood Knight doesn't have disadvantage on the attack roll

Evasion. When the Blood Knight is subjected to a Dexterity save it takes half damage on a failed save and no damage on a successful one.

Multiattack. The blood knight makes two longsword attacks, or one longsword attack and one poison dagger attack.

Longsword. Melee Weapon Attack: +10 to hit, reach 5 ft., 1 target. Hit: 11 (1d8 + 6) [slashing] damage. This weapon is cursed. Any non Order of Blood user must make a DC 15 wisdom save every morning whilst in possession of this weapon, or falls to the curse of the blade and attacks anything and everything without control(for this the DM takes control of such a character)

Poison Dagger.  Melee Weapon Attack: +7 to hit, reach 5 ft., 1 target. Hit:  6(1d4+4) [slashing] damage plus 18(4d8)  [poison] damage.

Uncanny Dodge. Whenever an attacker the Blood Knight can see hits you with an attack, you can use reaction to halve the attack's damage against it