Your Dexterity or Strength score increases by 2, and your Constitution score increases by 1.

Darkhalf mature at around the same rate as humans, yet can live up to around a thousand years.

Half Vampires' alignment differ greatly. If they were treated badly growing up, or were raised by their Vampire parent, they are likely to turn evil. Yet if they were treated with decency by their mortal community, they will, more than likely, tread the path of neutrality, or even good.

You are born a creature of the darkness, a child of the night. You can see in dim light within 60 feet of you as if it were bright light, and in darkness as if it were dim light. You can’t discern color in darkness, only shades of gray.

You can use this feature in both bat and humanoid form.

When you use the attack action on your turn, you may make a special Bite attack against a living creature within 5 feet of you. This attack counts as an unarmed strike in which you are proficient. You use your Dexterity modifier for attack rolls made with your Bite. On a hit, your bite deals 1d4 piercing damage + 1d4 necrotic damage, and you regain a number of hit points equal to the total damage dealt. The necrotic damage increases to 1d6 at 5th level, 1d8 at 10th level, 1d10 at 15th level and 1d12 at 20th level.

Being half vampire, you require the blood of another humanoid to to make up for that your body lacks. Once per day, when you are within 5 feet of a humanoid who is dead, you may use your Yearning Fangs trait to drain all the blood from that creature's body. This quantity of blood is sufficient to fuel you for a week (you no longer are required to eat or drink for this duration). In addition, while you are fuelled in this manner, you gain the following traits:

Twilight Shifting 

As an action on your turn, you can choose to transform into a bat. When you do so, all of your statistics change to that of a bat's, except for your Charisma, Wisdom and Intelligence scores. When your bat form drops to 0 hit points, you revert to your normal form. Any excess damage carries over to that form. If you are flying when you revert, you immediately fall to the ground, landing prone and taking the necessary falling damage, unless you have some way of preventing this. As an action on your turn, you can choose to end the bat form and revert to normal.

You can use this trait a number of times equal to your Charisma modifier (minimum of 1), and regain all expended uses when you finish a long rest.

Undead Fortitude

Your Constitution score increases by 2, to a maximum of 20. In addition, the first time you drop to her hit points on your turn, you may choose to drop to 1 instead. Once you have used this feature, you must finish a long rest before being able to use it again.

Beguiling 

You can cast the friends cantrip at will.

However, if you go an entire week without sufficiently fuelling yourself in this manner, you gain a level of exhaustion (this effect stacks for each week; one fuelling removes all levels of exhaustion gained in this way).

You have a base walking speed of 30 feet.

You can speak, read and write Common, and one other language of your choice