Belgoss Dyrr, Warden of Coin

Regeneration. Belgoss regains 10 hit points at the start of its turn if he has at least 1 hit point and isn’t in sunlight or running water. If Belgoss takes radiant damage or damage from holy water, this trait doesn’t function at the start of his next turn.

Spellcasting. Belgoss is an 10th-level spellcaster. His spellcasting ability is Charisma (spell save DC 15, +7 to hit with spell attacks). He has the following sorcerer spells prepared:

Cantrips (at will):booming blade, friends, mage hand, poison spray, 

1st level (4 slots):charm person, ray of sickness, Tasha's caustic brew

2nd level (3 slots):hold person, blindness/deafness, misty step

3rd level (3 slots):lightning bolt, slow, stinking cloud

4th level (3 slot):charm monster, confusion

5th level (2 slot):cloudkill, dominate person

Sorcery Points. Belgoss has 10 sorcery points. He can spend 1 or more sorcery points as a bonus action to gain one of the following benefits:

Heightened Spell: When Belgoss casts a spell that forces a creature to make a saving throw to resist the spell's effects, he can spend 3 sorcery points to give one target of the spell disadvantage on its first saving throw against the spell.

Quickened Spell: When Belgoss casts a spell that has a casting time of 1 action, he can spend 2 sorcery points to change the casting time to 1 bonus action for this casting. 

Spider Climb. The vampire can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.

Vampire Weaknesses. The vampire has the following flaws:

Stake to the Heart. If a piercing weapon made of wood is driven into the vampire’s heart while the vampire is incapacitated in its resting place, the vampire is paralyzed until the stake is removed.

Sunlight Hypersensitivity. The vampire takes 20 radiant damage when it starts its turn in sunlight. While in sunlight, it has disadvantage on attack rolls and ability checks.

Multiattack. Belgoss makes two attacks, only one of which can be a bite attack.

Rapier. Melee Weapon Attack: +8  to hit, reach 5 ft., one creature. Hit: 8 (1d8 + 4) piercing damage.

Bite. Melee Weapon Attack: +6 to hit, reach 5 ft., one willing creature, or a creature that is grappled by the vampire, incapacitated, or restrained. Hit: 7 (1d6 + 4) piercing damage plus 7 (2d6) necrotic damage. The target's hit point maximum is reduced by an amount equal to the necrotic damage taken, and the vampire regains hit points equal to that amount. The reduction lasts until the target finishes a long rest. The target dies if this effect reduces its hit point maximum to 0.

The vampire can take 3 legendary actions, 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. The vampire regains spent legendary actions at the start of its turn.

Move. The vampire moves up to its speed without provoking opportunity attacks.

Unarmed Strike. The vampire makes one unarmed strike.

Bite (Costs 2 Actions). The vampire makes one bite attack.