Blood Priest

Blindsight. This creature has blindsight out to 15 feet

Spellcasting. The [monster name] is a 12th-level spellcaster. Its spellcasting ability is [Wisdom] (spell save DC 18, +9 to hit with spell attacks). The [Blood Priest] has following [Warlock] spells prepared:
Cantrips (at will): Blade Ward, Chill touch, Eldritch Blast, True Strike 
5th level (3 slots): Hex, Crown of madness, Misty Step, Vampiric Touch, Blight, Scrying

Once per day: Circle of death

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

Evasion. When the Blood Priest is subjected to a Dexterity saving throw it takes half   damage on a failed save, and no damage on a successful save

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

*Please note that the Blood Priest uses Wisdom instead of Charisma as its spellcasting modifier. This is due to narrative reasons alone. In the Order of Blood Charisma is generally very low*

Multiattack. The blood priest can make two attacks with its poison dagger, or make one attack with its poison dagger and cast Flesh Rend

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

Flesh Rend. Ranged Weapon Attack: +11 to hit, range 60 ft., 1 target. Hit: 11 (1d8 + 7) force damage. The Blood Priest can use this spell when within 5ft. of an enemy creature.

 Uncanny Dodge. When an attacker that the Blood Knight Priest can see is hit with an attack, it can use its reaction to halve the damage dealt to it.

Blood Strike. When the Blood Priest is hit with an attack that does 25 damage or more, it can activate its Blood Strike. The Blood Strike allows the Blood Priest to use its Flesh Rend, but the damage is the amount of damage that was dealt to it.