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

Necrotic; bludgeoning, piercing, and slashing from nonmagical attacks

Darkvision 60 ft.

You know common and one other language of choice

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

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.

2 Melee Weapon Attacks. The vampire spawn has 2 melee weapon attacks which can be used as an action or bonus action depending on class.

Claws. Melee Weapon Attack: Strength Modifier to hit, reach 5 ft., one creature. Hit: 2d4 + Strength Modifier slashing damage. Instead of dealing damage, the vampire spawn can grapple the target escape DC 10 + Strength Modifier

Bite. Melee Weapon Attack: Strength Modifier to hit, reach 5 ft., one willing creature, or a creature that is grappled by the vampire spawn, incapacitated, or restrained. Hit: 1d6 + Strength Modifier piercing damage plus 2d6 necrotic damage. The target’s hit point maximum is reduced by an amount equal to the necrotic damage taken, and the vampire spawn 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 targets one humanoid it can see within 30 feet of it. If the target can see the vampire, the target must succeed on a DC 15 Wisdom saving throw against this magic or be charmed by the vampire. The charmed target regards the vampire as a trusted friend to be heeded and protected. Although the target isn’t under the vampire’s control, it takes the vampire’s requests or actions in the most favorable way it can, and it is a willing target for the vampire’s bite attack.

Each time the vampire or the vampire’s companions do anything harmful to the target, it can repeat the saving throw, ending the effect on itself on a success. Otherwise, the effect lasts 24 hours or until the vampire is destroyed, is on a different plane of existence than the target, or takes a bonus action to end the effect.

Ability score increase to 16 for Str, Dex, and Con if not higher.