So my players have been buzzing about the new DLC for Mortal Kombat and I must admit, I like the idea of a Shokan-inspired race, big, powerful, four limbs, draconic heritage and a proud warrior culture, but how would it be implemented without becoming game-breaking?

Obviously, the four arms becomes their main draw. Additional limbs means that while the Shokan can wield multiple weapons, or two two-handed weapons, they can't make more attacks than their Class Levels would allow. Writing it so that you can't cheese carrying 2 shields also seems a must, but allowing the player to have two (or more) free hands while still holding a weapon or hanging off a rope or ledge allows them some interesting lee-way, such as casting spells in normally impossible physical situations or allowing them to use tool-kits like a Thieves' Toolkit while holding themselves up with the majority of their limbs could be fun.

Possibly tie it into a Racial Ability called 'Ambidextrous', allowing the Shokan-themed race to use one set of arms to perform one task, so long as it is relatively simple, while the other set performs a more complex task that requires Proficiency, either in a Skill or a Tool Kit? For example, a Shokan Rogue with Proficiency in Athletics and Thieves Tools could easily pull off opening a locked window while holding onto a ledge, or if they had no proficiency in Athletics, they could still make an unarmed check and perform their Thieves Tool attempt with Proficiency, but if the Shokan lacked proficiency in both of those skills, then they could not use this Ambidextrous racial skill, or would be forced to use both Skill and Tool with Disadvantage? 

Stat wise, a +2 to Strength and a +1 to Dexterity?

Powerful Build seems a must, and possible a racial bonus to Athletics involving jumping seems plausible without being game-breaking.

Dark Vision? On the one hand, it is always useful, but on the other having them be night-blind and needing torches is often fun for a physically powerful race to have to deal with.

So, using the Musicus Meter, assuming 3 points for their Stat Score, 0.5 for Powerful Build, 2 points for the Ambidextrous Racial Skill, 1 point for doubling the amount of distance they can leap and being naturally proficient in the Athletics Skill and access to the Firebolt Cantrip just for flavour for an addition 1 point, bumping it up for the wording of the spell allowing it to be used on any target, not just any creature, and we have a formidable physical race for players to use.

How would you build it? I generally use the Musicus Meter when writing up Homebrew Races and always aim to make races around 8 points worth of abilities just to make everything feel more balanced and fun, rather than having players eager to push every scrap of advantage out of their character/race combo as well as making a fun RP character always picking the exact same thing and then having to pretend it isn't 'their OC' every other campaign.

Look into discussions of Thri-kreen as PCs in 5e. They are a four limbed race who used to be available for PCs in older editions.

I mean tbh having a four armed character isn't as big of a threat as everyone thinks the worst you can do is dual wield an extra great sword and get 1 extra attack as your bonus action per turn which In the grand scheme of things when you have a fighter sub class who can take 16 attacks per turn (samurai after class ability with advantage and action surge) what's a 17th attack gunna really hurt it at lower levels a 13th or 9th it really losses it's luster after extra attack levels and usually you'll have more options for your bonus action than getting that extra hit that being said shokan in mortal combat are half dragons they have fire elemental powers martially adept and massive I'd say they are on the big side of medium 8-9 foot tall stat block 2s 2e maybe even a penalty to dex they aren't stupid they are good tacticians but don't seem extraordinarily smart  count them as large creatures for carrying give them a 20 foot leap attack with a DC save to knock target prone dragonborns fire breath weapon and advantage on grapple checks along with the ability to dual wield 2 handed weapons they might be a little broken early game but late game most of your racial stuff will be boring and useless besides your leap which will be useful to knock people prone for your party to eat alive and your 4 stat stay block you'll never waste your full action on wimpy dragon born breath weapon when you could have your attacks or spells going off instead and an extra 2d6 +10 great sword damage with two weapon fighting means next to nothing you might be able to out wrestle a kraken though your basically just an edgy Goliath might even throw in some passive ac buff lore wise they have dragon hide and it would make them interesting +1 to armor class and you are 13 ac unarmored making you a solid monk/barbarian with their bonuses to unarmored these are all racial traits already in the game an not likely to break it besides the dual wielding big boy weapons still might have the strongest lvls 1-3 and the dm might have to adjust for that in your party just deal with the dm on hammering out if not all these abilities which ones he would allow or anything special you wanna add into it home brew can be as broken or as balanced as the dm allows and is prepared to go up against in his encounters

Having 4 arms is a big advantage in terms of the number of things that you can carry, but that's about it. The character will still be bound by the normal rules for making attacks and using a bonus action to make an additional attack. You gain no additional AC bonus for carrying more than one shield (specified in the core rules somewhere). 

I'd give them a racial ability to grapple opponents using the two additional arms: advantage on Grapple checks, and can wield a weapon+shield or two weapons whilst grappling.

Advantage on checks related to climbing, increased carrying capacity.

+2 Str, +1 Con seems right as racial bonuses, but since we now have customisable origins from Tasha's, it doesn't matter so much.

Shield + PAM or GWM is strong enough that I'd add a clause that you can't wield a heavy weapon and a shield at the same time. Even with extra arms, it would be really awkward to swing a polearm or greataxe while also effectively wielding a shield.

Simic Hybrid is an existing example of a race with extra arms. Limiting what they can do to an explicit list seems like an effective way to avoid unwanted abuse. This approach is how 4e handled Thri-kreen as well.

I might go with the following racial abilities 

Multiarm fighting: You can hold up to four weapons, provided each weapon is one-handed and has the light property. If you are holding a two-handed weapon, you can hold up to two additional weapons with your other hands. As a bonus action on your turn, you can make a number of additional weapon attacks using one-handed weapons you are holding equal to half the total number of weapons you are holding (rounded down). You do not add your ability modifier to the damage rolls for these attacks.

Multitasker: As a bonus action you can take the Use an Object action provided you have at least one hand free. 

Quote from Kaboom979 >>

I might go with the following racial abilities 

Multiarm fighting: You can hold up to four weapons, provided each weapon is one-handed and has the light property. Alternatively, you can hold up to two weapons with the two-handed property. As a bonus action on your turn, you can make a number of additional weapon attacks equal to half the number of weapons you are holding (rounded down). You do not add your ability modifier to the damage rolls for these attacks. 

 What about two one-handers and a two-hander at the same time?

I actually don't think you should get a swing with a two-hander on a bonus action. That's too good for a racial.

Quote from Wysperra >>

Quote from Kaboom979 >>

I might go with the following racial abilities 

Multiarm fighting: You can hold up to four weapons, provided each weapon is one-handed and has the light property. Alternatively, you can hold up to two weapons with the two-handed property. As a bonus action on your turn, you can make a number of additional weapon attacks equal to half the number of weapons you are holding (rounded down). You do not add your ability modifier to the damage rolls for these attacks. 

 What about two one-handers and a two-hander at the same time?

I actually don't think you should get a swing with a two-hander on a bonus action. That's too good for a racial.

 A fair point. I will change it 

Two unarmed strikes as a BA is crazy good as well. That's infinite flurry of blows. I would caution messing with action economy.

If you haven’t looked at the Sonic Hybrid, you should since it’s the only official PC race with a potential to get four arms in all of 5e. They deliberately minimized the impact on action economy, and it’s still so powerful the additional arms don’t become available until 5th level.

While Simic Hybrid has additional "appendages" rather than full additional arms, they're special ones for attacking/grappling specifically. For four normal arms I'd maybe go for something along the lines of:

Additional Arms

You have a total of up to four fully functional arms and hands. For the purposes of using equipment (such as weapons, shields etc.) you must choose only two of these to use during each turn. However, you may use any number of free hands to fulfil the requirements for spellcasting, grappling etc.

So it gives you more flexibility, and lets you do stuff that requires a free hand even if you have both main hands occupied. This means you could be a spellcaster with a shield and weapon without War Caster, or you could have a rapier and hand crossbow and still be able to reload it, or just have access to four weapons so you've always got options.

Might be a cleaner way to word it, but this should keep it useful while not being too powerful I think?

Samurai can only do that once per turn so at most it can get 6 attacks per turn if it is duel wielding light weapons