Can I use multiple hands for one attack, using this 6-Handed-Ones homebrew race?

Question

I am playing D&D 5e, with some homebrew elements.

I happen to have started a character with the 6-Handed Ones homebrew race by monrester. This race has the Multihands feature:

You have 6 hands. You can only attack once unless you you have Multiattack. You can hold more than one weapon, but can only use 1 per turn. Say you were holding a greatsword and a longbow. On one turn, you could attack with the greatsword, then the next turn attack with the longbow. You can only benefit 1 shield using this ability.

I want to play a monk. I was curious as to whether the following is allowed.

Can I use 3 fists in one punch? Or is that considered a multiattack and not allowed?

To be more specific, my character has 6 arms. I'm trying to use 3 of them in one attack - not multiple attacks, but one single strike. Does this work?

If it does work as I've described, would the damage look like (1d6)×3? Or can I only strike with one fist per turn, i.e. 1d6 flat damage?

Answer 1

Your unarmed strikes do not gain mechanical benefit from extra hands

Fluff-wise, there is no constraint regarding what your unarmed attacks actually represent. It could be punches, chops, kicks, headbutts, things like that. However, a single unarmed attack deals the same damage as usual, and in order to do multiple attacks, you need features like the Monk's Martial Arts or Flurry of Blows, or normal extra attacks, to get more attacks per turn. If we were meant to assume the homebrew race is supposed to grant extra attacks or augment the damage of unarmed strikes, the description of the homebrew race's feature should say so.¹

Note that extra free hands do not grant extra attacks or unarmed strike damage to anyone else, either. A character with two free hands deals the same damage as an otherwise identical character who has no free hands and opts to kick their enemies instead.

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¹ A little footnote pertaining to the racial feature's wording: a literal reading of the racial feature makes the race LESS capable of multiple attacks per turn than other characters. The phrasing "you can only use 1 [weapon] per turn" disallows Two-Weapon Fighting (or spreading extra attacks between different weapons), the first clause disallows multiple attacks from Martial Arts, Flurry of Blows, and any other source that isn't "Multiattack" (presumably meaning the "Extra Attack" class feature), and a very pedantic reader would also find issue with "You can only attack once" (as opposed to "...once per turn" or a similar wording).

Answer 2

Multihands does not benefit unarmed strikes

In terms of pure mechanics, using multiple hand on a single attack is no different to a single unarmed attack. You gain no damage bonus and it does not count as a 'multi-attack'. From the basic rules for melee attacks we have the following exert:

Instead of using a weapon to make a melee weapon attack; you can use an unarmed strike: a punch, kick, head-butt, or similar forceful blow (none of which count as weapons). On a hit, an unarmed strike deals bludgeoning damage equal to 1 + your Strength modifier. You are proficient with your unarmed strikes.

And from the Monk's Martial Arts feature:

• You can use Dexterity instead of Strength for the attack and damage rolls of your unarmed strikes and monk weapons
• You can roll a d4 in place of the normal damage of your unarmed strike or monk weapon. This die changes as you gain monk levels

These as the rules that you care about when making an unarmed strike. You can describe the attack however you like. "A punch, kick, head-butt, or similar forceful blow" such as a triple-punch are all considered equivalent. As a monk you can either use Strength or Dexterity for these attacks and you deal 1d4 + modifier damage. This dice increase at 5th, 11th and 17th level.

Thematically though you can describe your attack as multiple fists striking at once. You can do this for each of your unarmed strike, even the additional ones from Flurry of Blows. I can see some very cool descriptive combat from a multi-armed monk.

Where it does benefit you

The mechanical benefit of your Multihands feature could be useful for a Way of the Kensei Monk. As one of the few monastic traditions that rely on weapons for their attack you would be able to wield both a melee and ranged weapon simultaneously.

Essentially the main benefit of this feature is to allow you to be wielding more weapons at the same time, giving you more options on your turn. You could carry a heavy weapon and use Great Weapon Master one turn. Then switch to a Longbow on the next without using an item interactions. All this while getting the AC bonus from a shield (not when playing as a Monk like you are though).

Getting Multiattack as a PC

Gaining multiattack as a PC is extremely difficult. No class gets it as a feature and there are no feats you can take. Note multiattack is distinctly different from Extra Attack, the class feature which Monk (and others) get. One way you can obtain it is by becoming a lycanthrope, as they get multiattack.

If you do manage to get it, remember that Multiattack is not the same action as Attack and does not qualify as a trigger for your Flurry of Blows feature which requires the Attack action.