You are considered to be both a Humanoid and a Monstrosity.

You are Medium or Small. You choose the size when you select this race.

Your walking speed is 30 feet.

Character level 1

• You have darkvision out to 120 feet.

Character level 3

• Once per day you can cast alter self  without requiring concentration or components, but you can only manifest Natural Weapons or Change Appearance to resemble humanoids you have fed on.

Character level 5

• Once per day as a Bonus Action you can sprout bat-like wings the color of your own skin. In daylight you gain a flying speed of 30 feet and in darkness it increases to 50 feet (this trait does not grant a hover speed). The wings meld grotesquely & painfully into your back after 1 minute or until you end the transformation it as a Free Action.

While you are incredibly resilient, your genetic makeup is fragile as a result of how you were created. You are subject to the following weaknesses:

• You are vulnerable to Radiant damage.
• While in direct daylight you cannot spend hit dice or be healed by any means, except spending hit dice during feeding. If targeted by Revivify or a similar spell while in daylight you are only stabilized, not returned with hit points.
• Your altered body resists transmutation effects that aren't your own. When you are targeted by a transmutation spell or ingest a potion that alters your physical body (gaseous form, stone skin, enlarge/reduce, polymorph, etc.), you must immediately roll a D20. On a 10 or lower you are unchanged and you suffer one point of exhaustion. If you have a class feature which alters your physical form, they are exempt from this penalty.

Feeding on the blood of another creature might be an enjoyable experience for you, or it might be a trait you are disgusted by. It isn't required to keep you alive and you can survive off of normal food and other sustenance. However, feeding provides multiple benefits, and without feeding your normal lifespan will only be around 50 years.

Feeding on blood at least once per month grants you a lifespan comparable to an elf, and you immediately gain the following benefits:

• While feeding you can choose to spend a number of unspent hit dice equal to your proficiency bonus.
• Feeding cures any blindness, diseased, poisoned, exhaustion, frightened, or aging effects that you were subjected to within the last 24 hours.
• Your body doesn't require food or drink for the next 3 days.

These are the requirements and consequences of feeding on blood:

1. Feeding takes 1 minute and the amount of blood required can only be provided by a Humanoid or Beast that is Small or larger.
2. While feeding: your movement speed is 0, you have disadvantage on Perception checks, and you are choosing to be incapacitated.
3. The creature must be alive at the time of feeding or died within the last 10 minutes. If you feed on a creature who has been dead longer than 10 minutes, you gain no benefits and are poisoned for the next 24 hours. If you feed on a creature that was diseased, your GM may ask you to make a Constitution saving throw appropriate to the severity of the disease; a failed save grants no benefits and become afflicted yourself.
4. If a creature is alive when you finish feeding, they suffer necrotic damage equal to 5 times your character level and psychic damage equal to 1d8 + your character level. They must also succeed a DC 14 Wisdom saving throw equal to 10 + your proficiency bonus or be frightened of you for 24 hours.
5. If you are of neutral or good alignment and feed on a creature that is non-hostile you immediately have disadvantage on Wisdom saving throws for the remainder of the day. This penalty can only be removed by the greater restoration spell.
6. If feeding on an ally reduces them to 0 hit points, they immediately have disadvantage on death saving throws for the remainder of the day. This penalty can only be removed by the greater restoration spell.

From the above list, consequences 3 through 6 can each be removed by a wish spell.