The following are effects that you gain when transformed.

• You can not speak, though you can understand and communicate with other wolves and werewolves. You have advantage on Charisma (Persuasion) checks towards other wolves.
• Your Strength score increases by 2, your Strength can not exceed 20 in this way. Your size increases by 2 ft. and your weight increases by 150 lbs. but you are still considered medium.
• Your Armor Class equals 12 + your Dexterity modifier.
• You are resistant to bludgeoning, piercing, and slashing damage from nonmagical, nonsilvered weapons.
• Your speed increases by 10 ft., your speed cannot exceed 40 ft. in this way.
• You gain advantage on Wisdom (Perception) checks that rely on hearing or smell.
• You gain a +3 bonus to all intimidate and survival checks.
• You gain a +2  bonus to passive perception and perception checks.
• You gain a Bite attack: Melee Weapon Attack, one target, 1d8 + your Strength modifier piercing damage + necrotic damage equal to your Constitution modifier. The target’s hit point maximum is reduced by an amount equal to the necrotic damage taken, and you regain hit points equal to that amount. The reduction lasts until the target finishes a long rest. The necrotic damage for your Bite increases by 1d6 when you reach 5th level (1d6), 10th level (2d6), and 15th level (3d6). If the target is a humanoid, it must succeed on a DC 12 + your Constitution Modifier, Constitution Saving Throw or be cursed with werewolf lycanthropy and vampirism. In addition, you gain a Claw attack.  Melee Weapon Attack, one target, 2d6 + your Strength modifier slashing damage. 
• You gain a Pounce attack. If you move 15 feet in a straight line, you can make a bite attack against a target. On a hit, the target must make a Strength Saving Throw, DC equal to 10 + your Strength modifier + your proficiency bonus, or be knocked prone. The target must make another Strength Saving Throw, DC 10 + your Strength modifier + your proficiency bonus or be grappled by you. If you manage to knock prone your target, you can make a claw attack against it as a bonus action.

Your Werewolf form lasts for a number of hours equal to your Constitution modifier (minimum of 1) and ends early if you are knocked unconscious or reduced to 0 hit points. You can end your Werewolf form early by using an action on your turn.

You can attempt to sire any creature that has gained the lycanthropy vampirism curse through your Bite attack. At 6th level, you can attempt to sire one creature by making a DC 15 Charisma (Persuasion) check. If you succeed, then they will follow orders to the best of their ability at the DMs discretion. If you fail, then they will become hostile towards you. The number that you can sire this way increases by one every level thereafter.

Although vampires can be incredibly strong, their curse still comes with several notable drawbacks. Regardless of if you are a vampire spawn or a true vampire, you are affected by the following weakness unless specified otherwise:

• Forbiddance: You can't enter a residence without an invitation from one of the occupants.
• Running Water: Your flesh is torn apart in the presence of water, you take 20 acid damage when you end your turn in running water. This damage may not be reduced in any way.
• Stake to the Heart: If a piercing weapon made of wood is driven into your heart while incapacitated in your coffinlike structure, you become paralyzed until the stake is removed if you are a true vampire. However, if you are a vampire spawn, you are instead destroyed.
• Sunlight Hypersensitivity: You sear and burn in the light of the sun, your flesh immolating. If you end your turn in direct sunlight, you take 20 radiant damage. You also have disadvantage on any attack rolls and ability checks when in direct sunlight.

Your creature type is considered to be both humanoid and undead.

Dark magic sustains you, making you resistant to necrotic damage. Healing potions do not have a healing effect on you. Instead, they deal poison damage equal to the amount that was meant to heal. To heal you must either drink blood, spend hit dice, or finish a long rest.

Even though you are undead, you still require sustenance in the form of blood to sustain your unholy existence. You are immune to diseases. You do not need to eat or breathe, but you can ingest food and drink if you wish, though this food is always bland and stale to you. If you go for longer then seven days without drinking at least one ration of blood, at the midnight of the seventh day and every midnight on days thereafter, you suffer one level of exhaustion, which can only be removed by drinking a ration of blood. After consuming one ration of blood, you recover all levels of exhaustion caused by this trait. If you reach six levels of exhaustion due to this trait, you are indefinitely paralyzed. The only way to remove this paralyze is to be exposed to a rations worth of blood.

A ration of blood is a vial, roughly 4 ounces and while that is just enough to sustain you each week, you still feel the urge to drink and may still appear twitchy or ravenous in the heat of battle or when treating a wounded ally. A pint, such as that contained within a flask is considered a healthy amount, enough to keep you sustained while also suppressing your less civilized behavior. Each ration of blood heals you for 1d4 + 1 hit points while a pint will heal you for 2d4 + 2 hit points.

You can see in dim light within 120 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.

All vampires have sharpened teeth capable of tearing flesh from bone and draining blood from the body. If a willing, paralyzed, charmed, incapacitated, restrained, or grappled, creature within 5 feet of you has blood, you may use your bonus action to Bite them dealing 1d6 piercing damage and draining their blood dealing additional necrotic damage equal to your Constitution modifier. The target’s hit point maximum is reduced by an amount equal to the necrotic damage taken, and you regain hit points equal to that amount. The reduction lasts until the target finishes a long rest. Drinking blood this way is equal to consuming a ration as per your Blood Drinker trait but you do not regain additional hit points in this way. When you use your Bite, you can choose to not deal damage. The necrotic damage for your Bite increases by 1d6 when you reach 5th level (1d6), 10th level (2d6), and 15th level (3d6).

As a vampire you have a set of claws, your claws are natural weapons, which you can use to make unarmed strikes. You may use your Strength or Dexterity modifier for your attack and damage rolls with your claws. If you hit with them, you deal 1d6 slashing damage instead of the bludgeoning damage normal for an unarmed strike.

At 5th level, you gain the ability to regain 5 hit points at the start of your turn if you have at least 1 hit point and isn't in sunlight or running water. If you take radiant damage or damage from holy water, this trait doesn't function at the start of your next turn. At 10th level, you regain 10 hit points in this way instead and at 15th level, you regain 15 hit points in this way and at 20th level, you regain 20 hit points in this way.