Many classes have means of turning Vampiric Bite magical...
But not all of them are built the same.
I've been dealing with methods to turn Vampiric Bite into a magical attack since Van Richten's Guide to Ravenloft first released, and since then there have been many ways for classes to turn this into a magical bite (spellcasters in particular). Firstly, let's go over what Vampiric Bite actually does so we know the rules going forward:
Your fanged bite is a natural weapon, which counts as a simple melee weapon with which you are proficient. You add your Constitution modifier, instead of your Strength modifier, to the attack and damage rolls when you attack with this bite. It 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 attack with this 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:
- You regain hit points equal to the piercing damage dealt by the bite.
- You gain a bonus to the next ability check or attack roll you make; the bonus equals the piercing damage dealt by the bite. [...]
Now, from RAW, what we know about the Vampiric Bite is this:
- It is considered a simple melee weapon you are proficient with, not an unarmed strike.
- You gain advantage when your hit points are below half when making this attack.
- It uses the character's Constitution modifier, requiring you to deep dip into Constitution to use it effectively.
- It cannot empower the player when used to attack Constructs or Undead, meaning your only real reason for using it is nonexistent on these two creature types.
- Both of its empowerments only account the piercing damage dealt by the bite. This means that added damage types will not benefit the empowerment.
Regardless of these facts, there are still options to turn these weapons magical.
The ways I've found thus far are listed below:
Magic Weapon (2nd level) | [Artificer, Paladin, Ranger, Sorcerer, Wizard]
You touch a nonmagical weapon. Until the spell ends, that weapon becomes a magic weapon with a +1 bonus to attack rolls and damage rolls.
This is more effective if you're a Barbarian with a spellcaster ally who doesn't have any notable Concentration Spells at the moment (don't expect this to happen often). But because all it does is turn your weapon magical, it isn't the best it could be.
It's also not even the best option for Artificer, but the best for Ranger.
Enhanced Weapon (Artificer Infusion) | [Artificer only]
Item: A simple or martial weapon
This magic weapon grants a +1 bonus to attack and damage rolls made with it.
The bonus increases to +2 when you reach 10th level in this class.
This is the outright best option for an Artificer in terms of making your fangs magical. It is permanent, it does not add additional damage types, and it gives a +1 (and later +2) bonus to your attack and damage rolls.
However, it still requires you to invest into Constitution for it to remain useful. An issue with almost every method on this list.
Radiant Weapon (Artificer Infusion) | [Artificer Only]
Prerequisite: 6th-level artificer
Item: A simple or martial weapon (requires attunement)
This magic weapon grants a +1 bonus to attack and damage rolls made with it.
The weapon has 4 charges. As a reaction immediately after being hit by an attack, the wielder can expend 1 charge and cause the attacker to be blinded until the end of the attacker's next turn, unless the attacker succeeds on a Constitution saving throw against your spell save DC.[...]
This is a secondary option to Enhanced Weapon for Artificers, though by no means better. The Infusion also allows your fangs to shed bright light for 30 ft. and dim light for a further 30 ft., but you already have Darkvision out to 60 ft., which makes this redundant.
The only reason I would choose this as my Infusion over Enhanced Weapon is because of the reaction to blind opponents that hit me, and that is a very niche case in most circumstances.
Elemental Weapon (3rd Level) | [Artificer, Druid, Paladin, Ranger]
A nonmagical weapon you touch becomes a magic weapon. Choose one of the following damage types: acid, cold, fire, lightning, or thunder. For the duration, the weapon has a +1 bonus to attack rolls and deals an extra 1d4 damage of the chosen type when it hits.
This is actually just as bad as Magic Weapon, because while you're getting extra elemental damage for the duration, your bite cannot benefit from that because it specifically requires piercing damage for all of its empowerments.
But it's also your best (and only) option for Druids when it comes to spells.
Holy Weapon (5th Level) | [Cleric, Paladin]
You imbue a weapon you touch with holy power. Until the spell ends, the weapon [...] deal[s] an extra 2d8 radiant damage on a hit. If the weapon isn’t already a magic weapon, it becomes one for the duration. [...]
Again, it's okay if you just want to make your Vampiric Bite magical, but the radiant damage does not benefit your Vampiric Bite's empowerment in any way. And considering Radiant damage is frequently used against Undead, you have even less reason to use Holy Weapon on your fangs, because you don't want to be biting Undead.
Unfortunately, it's your best option for a Cleric or Paladin.
Way of the Kensei (Subclass) | [Monk Only]
Bear with me. This is going to be a loaded discussion, but a very interesting one. There's a reason I've added this, even though it isn't from a Spellcasting Class.
3rd level: Path of the Kensei
When you choose this tradition at 3rd level, [...] you gain the following benefits:
- Kensei Weapons. Choose two types of weapons to be your kensei weapons: one melee weapon and one ranged weapon. Each of these weapons can be any simple or martial weapon that lacks the heavy and special properties. [...] Weapons of the chosen types are monk weapons for you. [...]
- Agile Parry. If you make an unarmed strike as part of the Attack action on your turn and are holding a kensei weapon, you can use it to defend yourself if it is a melee weapon. You gain a +2 bonus to AC until the start of your next turn, while the weapon is in your hand and you aren’t incapacitated.
Kensei Weapons allows you to treat your fangs as a Monk weapon, which will increase their damage die; from a 1d4, to a 1d10 maximum at 17th level. This is the only way I've found thus far that allows you to increase your fangs' damage die. It also could change your fangs' scaling from Constitution to Dexterity, preventing you from being MAD.
Agile Parry is an interesting feature as well, though it's hard to know how it would work with your fangs. RAW, most DMs wouldn't allow you to use it because you are not holding them in your hand. However, rule of cool would allow you to catch an opponent's weapon beneath your teeth. Which I'd hope some DMs would find cool enough to handwave the RAW mechanics.
6th level: One with the Blade
At 6th level, you extend your ki into your kensei weapons, granting you the following benefits.
- Magic Kensei Weapons. Your attacks with your kensei weapons count as magical for the purpose of overcoming resistance and immunity to nonmagical attacks and damage.
- Deft Strike. When you hit a target with a kensei weapon, you can spend 1 ki point to cause the weapon to deal extra damage to the target equal to your Martial Arts die. [...]
Magic Kensei Weapons is when your fangs permanently turn magical. By this point, your fangs' damage die would have elevated to a d6 as well, which puts it above all other variations of magic fangs in terms of base damage.
Deft Strike increases this even further, turning your fangs' 1d6 into a 2d6, allowing you to deal up to a maximum of 17 magical piercing damage in a single attack.
11th level: Sharpen the Blade
At 11th level, you gain the ability to augment your weapons further with your ki. As a bonus action, you can expend up to 3 ki points to grant one kensei weapon you touch a bonus to attack and damage rolls when you attack with it. The bonus equals the number of ki points you spent. This bonus lasts for 1 minute or until you use this feature again. [...]
Sharpen the Blade arrives right when most players would be getting +2-3 magic weapons. At this level, your magic fangs now do 1d8 piercing damage. With Sharpen the Blade and Deft Strike, this becomes a maximum of 2d8+8, or 24 piercing damage in a single attack. Adding in Monk's optional Ki-Fueled Attack and Extra Attack, you can deal 4d8+24 piercing damage in a single turn, up to a maximum of 56 damage.
And while I didn't include it in the original overview of Vampiric Bite, its empowerment can be used up to your proficiency bonus before having to long rest. By spending 3 uses of your Vampiric Bite, you could heal yourself by 56 HP in a single round.
This is the time I mention that an 11th level Monk's hit point average, without accounting for Constitution, is 58. You are healing almost all of your HP in a single round.
17th level: Unerring Accuracy
At 17th level, your mastery of weapons grants you extraordinary accuracy. If you miss with an attack roll using a monk weapon on your turn, you can reroll it. You can use this feature only once on each of your turns.
Move over Divination Wizards, the Kensei Monk Dhampir is the dumbest way of ensuring damage. We haven't spoken much about one aspect of the Vampiric Bite: how you gain advantage on it when you are below half of your hit points. But now, with Unerring Accuracy, you can gain that even if you aren't once per turn. And, because RAW, Unerring Accuracy is not described as Advantage: If you miss an advantage-boosted attack from your Vampiric Bite, you can reroll it with that advantage still. Rolling 4d20 for accuracy sounds fun.
Add in Focused Aim, and you can also add up to +6 to these accuracy rolls.
Now, time for what you've been waiting for: calculating the maximum damage a Kensei Monk Dhampir can do in a single round (without factoring in magic items).
2d10+8 + 1d10+8 + 1d10+8 = 56 damage on average, or a maximum of 72 damage.
On average, a Monk with 10 in con will have 88 HP. Enjoy.
Battle Smith (Subclass) | [Artificer Only]
This one won't be nearly as long, but will go over how to turn your bite into a multi-target heal.
3rd level: Battle Ready
When you reach 3rd level, your combat training and your experiments with magic have paid off[...]:
- When you attack with a magic weapon, you can use your Intelligence modifier, instead of Strength or Dexterity modifier, for the attack and damage rolls.
Like our last discussion, Battle Ready should allow you to avoid going MAD by having to deep dip into Constitution. So long as your fangs are infused with Enhanced Weapon (or Radiant Weapon), you should be able to use your Intelligence over your Constitution.
9th level: Arcane Jolt
At 9th level, you've learn new ways to channel arcane energy to harm or heal. When [...] you hit a target with a magic weapon attack [...], you can channel magical energy through the strike to create one of the following effects [...]:
- Choose one creature or object you can see within 30 feet of the target. Healing energy flows into the chosen recipient, restoring 2d6 hit points to it.
Now, suddenly, once per turn when you bite with your fangs, you can both empower yourself and heal an ally at the same time. If you wanted to feel like a blood magic healer without homebrew, this is the way to do it.
15th level: Improved Defender
At 15th level, your Arcane Jolt [becomes] more powerful:
- The [...] healing of your Arcane Jolt [increases] to 4d6.
Now you're healing your ally for 4d6, and yourself for 2d4+7 at max. It's pretty skewed in their favor, obviously. But it's a fun way to top off your party's hit points and help with keeping them alive.
Tasha's Otherworldly Guise (6th Level) | [Sorcerer, Warlock, Wizard]
[...] All your weapon attacks are magical, and when you make a weapon attack, you can use your spell casting ability modifier instead of Strength or Dexterity for the attack and damage rolls. [...]
In my opinion, this is by far the best method of granting Vampiric Bite magic weapon status for spellcasters.
While you don't get the +1 to +3 bonus from the other spells, you should be able to use your spell casting ability modifier instead of Constitution. This spell is available to Sorcerers, Warlocks and Wizards.
Though it is only a 1-minute Concentration spell, it grants you many more benefits, such as a 40 ft. flight speed, an Extra Weapon Attack, +2 to AC. If you choose to align with the Lower Planes, you gain immunity to Poison and Fire damage, and the Poisoned Condition. And if you choose to align with the Upper Planes, you gain immunity to Radiant and Necrotic Damage, and the Charmed Condition (better in my opinion).
Originally this post was tailored specifically to spellcasters, but I've since made edits to add details on Kensei Monk and Battle Smith Artificer to break them down for those who don't know how they work. I'll continue making edits as time goes on and I discover more ways to make your teeth a magical murder weapon. Thanks for reading, and enjoy your feeding frenzies.