D&D 5E Dhampir Barbarian

[shadowoflameth]

The hexblade ability modifies an existing weapon, It is not a weapon itself.

The Dhampir bite is a new weapon, with stats as detailed in the lineage. Across the whole ruleset there are many new weapons that are not in the weapon table. E.g. the yklwa in ToA.

You may be thinking of the Pact of the Blade ability to create a weapon. Which you could use to create yourself a Dhampir bite if you wanted, because RAW is for idiots.

Correct, Hexblade modifies an existing weapon, it does not create a new kind of weapon, but it could not create a dhampir bite for the hexblade or change the effects of the bite. The Dhampir bite is not a new weapon as if it were a new variant on an axe or mace, but the bite counts as a weapon, just like unarmed strike counts as a melee weapon attack without actually being a melee weapon (confirmed in the errata), and unarmed strikes do appear on the weapon table. You can't remake your bite either with hexblade abilities because the bite is only something which the Dhampir can do which counts as using a weapon with stats described in the lineage. It's properties are Natural and Simple Weapon (only), and the Dhampir is proficient with it. If you want to add Special to that list, that's fine, but it's a house rule.

 

[Paul Farquhar]

unarmed strike counts as a melee weapon attack without actually being a melee weapon (confirmed in the errata), and unarmed strikes do appear on the weapon table.

Unarmed strikes may or may not appear on the weapon table, depending on which printing of the PHB you own. In the current version, it does not. And the errata is very clear that a weapon attack is not the same as an attack with a weapon. An unarmed strike is a weapon attack, but it is not an attack with a weapon. The Dampir's bite is an attack with a weapon, but it is not an unarmed strike, and cannot be used to make one (natural weapons that can be used to make unarmed strikes say so in the description).

 

[ECMO3]

Path of the Beast can give you a bite attack when you rage:

Spoiler

Bite. Your mouth transforms into a bestial muzzle or great mandibles (your choice). It deals 1d8 piercing damage on a hit. Once on each of your turns when you damage a creature with this bite, you regain a number of hit points equal to your proficiency bonus, provided you have less than half your hit points when you hit.

Dhampir also gives you a bite attack:

Spoiler

Vampiric Bite. Your fanged bite is a natural weapon, which counts as a simple melee weapon with which you are proficient. You add your Constitution modifier to the attack and damage rolls when you attack with your bite. Your bite deals 1d4 piercing damage on a hit. While you are missing half or more of your hit points, you have advantage on attack rolls you make with this bite.

When you use your bite and hit a creature that isn’t a Construct or an Undead, you can empower yourself in one of the following ways of your choice:

• regain hit points equal to the damage dealt by the bite
• gain a bonus to the next ability check or attack roll you make; the bonus equals the damage dealt by the bite.

You can empower yourself with your bite a number of times equal to your proficiency bonus, and you regain all expended uses when you finish a long rest.

How would you rule this interaction?

You can use either one but they do not stack.

There is also a mechanics difference in the two in that the Vampiric Bite is considered a natural weapon while the Barbarian Bite is an unarmed strike. For this reason the Barbarian Bite could be used with a Monk Martial arts attack if you were a mutliclass Monk-Barbarian