Vampire Spawn, Vanguard

Bloodthirsty. When the vampire is below half its hit point maximum, it has advantage on all melee attack rolls against creatures that aren’t Constructs or Undead. 

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

Unusual Nature. The vampire doesn’t require air.

Vampire Weaknesses. The vampire has the following flaws:

Forbiddance. The vampire can't enter a residence without an invitation from one of the occupants.

Harmed by Running Water. The vampire takes 20 acid damage when it ends its turn in running water.

Stake to the Heart. The vampire is destroyed if a piercing weapon made of wood is driven into its heart while it is incapacitated in its resting place.

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. The vampire vanguard makes one Bite attack and two Claw attacks. If the vanguard hits one target with both Claw attacks,  the target must succeed on a DC 15 Constitution saving throw or take 7 (2d6) slashing damage, and the vampire regains hit points equal to that amount.

Bite. Melee Weapon Attack: +7 to hit, reach 5 ft., one creature. Hit: 13 (2d8 + 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.

Claw. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 11 (2d6 + 4) slashing damage. Instead of dealing damage, the vampire can grapple the target (escape DC 15).

Fleet of Foot. The vampire takes the Dash action.