A lot of the build advice I have seen suggests crit-based builds. But that requires you to focus almost solely on the bite in the hopes of landing a critical hit to empower, when you usually have better attacks.

Well. . .

Sometimes an attacker wants to incapacitate a foe, rather than deal a killing blow. When an attacker reduces a creature to 0 hit points with a melee attack, the attacker can knock the creature out. The attacker can make this choice the instant the damage is dealt. The creature falls unconscious and is stable.

An unconscious creature is incapacitated, can't move or speak, and is unaware of its surroundings.

[...]

Attack rolls against the creature have advantage.

Any attack that hits the creature is a critical hit if the attacker is within 5 feet of the creature.

tl;dr Fight with a better weapon, knock out the enemy, and finish them off for an empowered, auto-crit bite.

Barring a clear answer to what "damage dealt" means, a DM could easily rule that because you're taking the target from 0 hp to 0 hp, you've dealt 0 damage for the purposes of the bite.  This sounds like potentially dangerous territory for a PC to build around.

A DM needs to rule on it anyway - does it mean how much you produce, or how much the target suffers after their rules apply?

Quote from quindraco >>

Barring a clear answer to what "damage dealt" means, a DM could easily rule that because you're taking the target from 0 hp to 0 hp, you've dealt 0 damage for the purposes of the bite.  This sounds like potentially dangerous territory for a PC to build around.

A DM needs to rule on it anyway - does it mean how much you produce, or how much the target suffers after their rules apply?

That would be a pretty egregious case of DM fiat.  Damage dealt to an unconscious character is not reduced to 0.  Precedent for this is in the Basic Rules (emphasis mine).

Damage at 0 Hit Points. If you take any damage while you have 0 hit points, you suffer a death saving throw failure. If the damage is from a critical hit, you suffer two failures instead. If the damage equals or exceeds your hit point maximum, you suffer instant death.

The last sentence would be irrelevant if RAW, that damage was 0.  So if a bite deals 2 damage, it deals 2 damage, regardless of the absence of negative hit points.

You can only empower a number of times equal to your proficiency bonus between each long rest, so having an entire build around empower would definitely be a little pointless.

Quote from Farling >>

You can only empower a number of times equal to your proficiency bonus between each long rest, so having an entire build around empower would definitely be a little pointless.

Totally agree.  There's a well-known website that was recommending using the bite exclusively on a Barbarian (so no rage bonus or Reckless attack) and Paladins in the hopes of critfishing for the empower.  While 2d4+X is a pretty big bump for skill checks and low-level healing, I don't think people should be building around it exclusively.

Quote from Farling >>

You can only empower a number of times equal to your proficiency bonus between each long rest, so having an entire build around empower would definitely be a little pointless.

I’m replying to point out the PUN-iness of calling a build about biting and piercing damage POINTLESS :)

I think a dampir based mercy monk would be pretty cool. The piercing damage would scale up with your monk die.  crit fishing with the piercer feat might be pretty cool since you actually get another piercing die. Your harm touch would replicate some of the crusher/slasher effects anyways I think?

Im sure there are many ways this would fall into The dreaded “DM FIAT” territory, but i think I’d definitely play that monk.

Quote from Bobbybaker >>

I think a dampir based mercy monk would be pretty cool. The piercing damage would scale up with your monk die.  crit fishing with the piercer feat might be pretty cool since you actually get another piercing die. Your harm touch would replicate some of the crusher/slasher effects anyways I think?

mom sure there are many ways this would fall into The dreaded “DM FIAT” territory, but i think I’d definitely play that monk.

Dhampir Kensei with the Piercer can deal 5 Martial Arts Die + CON mod + 3 magical piercing damage on a critical hit using Deft Strike and Sharpen the Blade features. 

Dhampir monk does require approval from your DM though.  I think it's been pointed out by forum staff, but Martial Arts explicitly only replaces attacks that you would make using Strength, which does not include the Vampiric Bite.  Most DMs would probably handwave that, but it is something to be aware of.

Quote from Ursus_the_Grim >>

Dhampir monk does require approval from your DM though.  I think it's been pointed out by forum staff, but Martial Arts explicitly only replaces attacks that you would make using Strength, which does not include the Vampiric Bite.  Most DMs would probably handwave that, but it is something to be aware of.

Actually, no, you don't. There are 3 benefits of Martial Arts that can apply to Monk Weapons:

1. Replacing the Strength Modifier used for the attack and damage rolls with Dexterity. 
2. Replace its damage dice with your Martial Arts Dice
3. Bonus action Unarmed Strike after using the Attack action. 

These three are unconnected and are all dependent on Monk Weapons/Unarmed Strikes. Monk Weapons are any Simple Melee Weapons that lack the two-handed or heavy properties. Vampiric Bite is a simple melee weapon, and it isn't heavy or two-handed, and thus is automatically a monk weapon. Benefit #1 doesn't RAW work on the Vampiric Bite, but Benefit #2 does, and isn't dependent at all on Benefit #1 working. 

However, this will make any Dhampir monk pretty MAD, as they'll have to focus on Constitution for their Bite, Dexterity for their AC, Unarmed Strikes, and other weapon attacks, and Wisdom for AC and Ki saving throws. 

Benefit #1 doesn't work RAW, Benefit #2 works perfectly fine RAW, as does Benefit #3 (but the bonus action attack RAW cannot be a Vampiric Bite). 

I stand  corrected.  Good point.

I don't think it makes the monk too MAD, either.  It is possible to build a monk that doesn't rely on Wisdom too much, so I could see a Con/Dex focused build functioning just fine.

How would you build that monk then?

Quote from honking1clown >>

How would you build that monk then?

Personally?  Using point buy, go 8/15/15/8/15/8.  Leave Wisdom at 16.

As pointed out, Mercy is a pretty solid choice, but any subclass that doesn't rely on 'special abilities' would be fine.  At level 8, you can easily have the Piercer feat, 18 in Dex and a 16 each in Con and Wisdom.

You can do better, sure, but it would look like this.

I mean the Dhampir could also go Warlock (Undead) and lets say he picked up Fey Touched (Hunters Mark) at level 4 - he should end up with 4d4+2d6+CON mod  necrotic damage - averaging at about 12+CON mod in damage. 

Maybe a houserule might be interesting here. If the target is at 0hp, the targets also dies if the Dhampir does more damage then its CON score.