Crimson Pact: Vladimir's body has become unnaturally tough and able to hold an unnerving amount of blood. Vladimir's hit dice is increased to a d12. If Vladimir is below 50% maximum health the damage inflicted upon himself by his abilities is halved (rounded down). Once below 25% maximum health, he ignores that damage completely.

Crimson Rush. If Vladimir hits two Transfusion attacks in a single round, his movement speed is increased by 15 ft. and his next Transfusion attack deals an additional (10) 3d6 necrotic damage until the start of his next turn

Multiattack: Vladimir makes two attacks with his Transfusion. Vladimir cannot target the same target with both attacks.

Transfusion. Ranged Spell Attack: +10 to hit, reach 45 ft., 1 target, Hit: 16 (3d6 + 6) [necrotic] damage. Vladimir heals for the same amount of necrotic damage dealt.

Hemoplague (Recharges after a Short or Long Rest): Vladimir spreads a virulent plague in a 20 ft. radius sphere within a 60 ft. range. Vladimir immediately takes 20 damage. All creatures within the area must make a DC 17 constitution saving throw or take (22) 5d8 disease damage and suffer from a disease for the next minute. While diseased in this way, the creature takes an additional  (4) 1d8 necrotic damage every time they are hit with an attack. A creature may repeat the save at the end of each of its turns. On a successful save, a creature is dealt half the damage and is not poisoned.

Tides of Blood (Recharge 4-6): Vladimir immediately takes 10 damage. Vladimir collects a nova of blood above his head. He may immediately explode the nova to force all creatures within 10 ft. of Vladimir to make a dexterity saving throw or take (11) 2d10 bludgeoning damage. If Vladimir waits to explode the nova until his next turn, all creatures within 20 ft. of Vladimir must make a dexterity saving throw or take (22) 4d10 bludgeoning damage and have their movement speed halved until the end of their next turn. Vladimir does not need to concentrate of Tides of Blood. On a successful save, a creature takes half the bludgeoning damage and are not slowed. 

Sanguine Pool (Recharge 6). When a creature hits Vladimir with an attack, Vladimir can melt into a pool of blood covering a 15 ft. square on the ground. Vladimir immediately takes 15 damage. Vladimir may move up to 20 ft. Vladimir can no longer be targeted by attacks or spell attacks, automatically succeeds on all strength, Dexterity, and constitution saving throws, and is immune to all damage except radiant, cold, and psychic damage until the start of his next turn when he emerges from the pool.

Any creature that enters or starts its turn in the blood pool must make a DC 16 Constitution saving throw or take 10 (3d6) necrotic damage. Vladimir heals for the same amount of necrotic damage dealt. 

Vladimir can take N-1 legendary actions (N = Number of PCs), choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature’s turn. Vladimir regains spent legendary actions at the start of its turn.

Transfusion (Costs 1 Action). Vladimir makes a Transfusion attack.

Move (Costs 1 Action). Vladimir moves up to his movement speed.