Last Updated: August 31, 2022
Bugs from space! Well, technically I think they originated from Dark Sun, but Athas hasn’t made a return in 5e. So within the 5e canon, thri-kreen are four-armed humanoid space bugs. They have other wonderful things about them, but the four arms are certainly the most unique and eye-catching.
Thri-Kreen absolutely thrive in Dexterity-based martial builds. With 13+Dex natural armor, you can match full plate’s AC once you hit 20 Dexterity. Chameleon Carapace allows you near-constant Advantage on Stealth checks to hide. Secondary Arms encourages the use of light weapons, the best of which are frequently also Finesse weapons. Thri-Kreen are also telepathic, further encouraging them to pursue sneaky, Dexterity-based builds.
Chameleon Carapace’s easy Advantage is certainly excellent, but remember that it’s only on checks to hide, not on checks to move silently or anything else. If you’re trying to stay still and avoid notice, you’re in good shape. If you need to sneak down a hallway, it won’t help you and your big stompy feet.
A burly, Strength-based thri-kreen is technically possible, but there’s little incentive to go that route. In fact, in many ways the Thri-Kreen’s traits pigeon-hole them into those Dexterity-based martial builds. Casters typically gain little benefit from the additional hands. Gish builds may find the ability to hold a weapon, a shield, and a focus at the same time helpful, but only to get around the frustrating rules for somatic components which nearly everyone ignores anyway (RAW you can’t use a focus to perform somatic components unless the spell has a qualifying material component).
Table of Contents
- Secondary Arms
RPGBOT uses the color coding scheme which has become common among Pathfinder build handbooks, which is simple to understand and easy to read at a glance.
- : Bad, useless options, or options which are extremely situational. Nearly never useful.
- : OK options, or useful options that only apply in rare circumstances. Useful sometimes.
- : Good options. Useful often.
- : Fantastic options, often essential to the function of your character. Useful very frequently.
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The Thri-Kreen’s signature trait is their Secondary Arms. This is the first race we’ve seen in 5e with more than two arms, and in a game where the rules are written for races with just 2 arms, they’re a complex rules subject. I’m going to explain how they work, what they can and can’t do, and how you can get the most out of your space bug.
What do the arms do?
I can’t reproduce the exact text of the rules because the Thri-Kreen isn’t included in the SRD. Grab your copy of Spelljammer: Adventures in Space, or check the Thri-Kreen page on DnDBeyond. The precise text is important, so I encourage you to read the text of Secondary Arms before continuing.
To paraphrase what your hands can do:
- Manipulate objects
- Open/close doors/containers
- Pick up or set down Tiny objects
- Wield light weapons
There are several things which a character can typically do with their hands which are notably omitted. This isn’t a comprehensive list, but here are some noteworthy things that you can’t do with your secondary arms:
- Grapple or Shove a Creature
- Perform somatic components
- Use a magic item
- Use a shield
- Use an Object (the Action)
- Wield a non-light weapon
There’s an important distinction between the phrase “manipulate an object” and the Action “Use an Object”. “Use an Object” includes things like using alchemist’s fire. Manipulating an object just means to handle it, such as by turning it over, carrying it, poking it, etc. A thri-kreen could flip a table, but they couldn’t drink a potion with their Secondary Arms. I believe that this was a deliberate balancing decision to prevent thri-kreen characters from breaking the “hand economy” too much.
Optimizing Your Arms
If you’re using two-handed weapons in your primary arms, your Secondary Arms are happy to hang out and look cool. You could wield light weapons like daggers and make ranged attacks with them in between attacks with your two-handed weapon. The same benefit applies if you’re using a shield a non-light one-handed weapon in your primary arms.
Where the Thri-Kreen shines is with light weapons. If you use your Secondary Arms exclusively for attacking, your more versatile primary arms are left for other purposes. Having four arms also has some exciting benefits for two-weapon fighting.
Consider a melee build around two-weapon fighting. Such a character will most likely use short swords or something similar to qualify for two-weapon fighting. Since the qualifying weapons are melee weapons with the Light property, you can use them both in your Secondary Arms, leaving your primary arms free.
But what do we do with your other arms? Whatever you want, really.
A shield is an obvious addition. +2 AC on top of the action economy of two-weapon fighting is very effective. Two-weapon fighting typically means giving up two-handed weapons and shields in exchange for an additional attack, and having Secondary Arms changes that trade.
You can also wield other weapons in your primary arms even if they don’t qualify for two-weapon fighting. You could wield a reach weapon like a glaive or a whip and use those weapons to make opportunity attacks. Since those attacks aren’t made as part of your Action/Bonus Action they don’t interact with two-weapon fighting in any way.
If you have Extra Attack, you can even use your primary arms in conjunction with two-weapon fighting to attack with weapons which don’t qualify for two-weapon fighting. The TWF rules require you to take the Attack action and attack with a light weapon to get the Bonus Action attack. Once you’ve met that requirement, you’re free to do what you like with your other attacks, including attacking with a two-handed weapon or even with a ranged weapon.
A character with Extra Attack could declare the Attack action, make one attack with a short sword in a secondary arm, then make their second attack with a greatsword in their primary arms. They’ve now qualified for two-weapon fighting, so they could then use a Bonus Action to attack with another light weapon wielded in their other secondary arm.
Finally, Secondary Arms eases the restrictions of the Loading property. A character wielding pistols or hand crossbows in three of their arms can still attack once with each of them on the same turn because the Loading property applies to each weapon individually. And, so long as you have a free hand, you can reload all three of your hand crossbows. Taking the Crossbow Expert or Gunner feats is certainly easier than juggling three weapons, and both feats come with other benefits, but this gimmick will allow you to make multiple attacks until you can fit a feat into your build.
Secondary Arms FAQ
Can I reload a weapon with my secondary arms?
The rules are technically unclear, but I would allow it. The rules for the Ammunition property state that “you need a free hand to load a one-handed weapon”. The secondary arms have hands on them, which qualifies.
Can I use a spellcasting focus in my Secondary Arms?
Yes, with some limitations. The focus must be tiny (a wand is fine, but I’m not sure if a staff is), and you can’t perform Somatic components. This would allow you to substitute the focus for any inexpensive material components which are not consumed by the spell, but you still need one of the hands on your primary arms to perform any Somatic components so the benefits of using a focus this way are minor.
Can I use secondary arms to wield a two-handed weapon?
No. You wield a two-handed weapon in two hands, and there are no two-handed weapons that also have the light property.
Can I use secondary arms to wield a Versatile weapon with two hands?
No. You are explicitly wielding a Versatile weapon in two hands and there are no weapons that are both light a versatile.
Do I get extra attacks for using Secondary Arms?
No. You still use the rules for two-weapon fighting even if you’re wielding three or four weapons.
Of every gish option there is, the Artificer is least in need of additional hands. The Tools Required feature specifically mandates that you need to have a focus in hand to cast spells, and since that focus can be an infused item you’re free to operate with a shield in one hand and either a weapon or a tool in the other. Even Chameleon Carapace is redundant since armor artificers can easily produce Advantage on Dexterity (Stealth) checks and 13+ armor is replaceable with infused items.
For barbarian subclasses which lack a consistent use for their Bonus Action (totem warrior, etc.), two-weapon fighting is a tempting option for boosting your damage output, allowing you apply your rage bonus to damage an additional time. However, the damage output gained from doing so is typically smaller than what you give up for using a two-handed weapon, and if you’re not using a two-handed weapon you typically want to use a shield.
Secondary Arms offers an opportunity to use two-weapon fighting alongside either a shield or a two-handed weapon. Until you get extra attack you can go handaxe+handaxe+shield, then at level 5 you might switch to handaxe+handaxe+greataxe, attacking once with each, or you might stick to the handaxes and shield. Three attacks with the handaxe, despite losing your ability score bonus on the Bonus Action attack, will exceed the DPR of a two-handed weapon.
If we compare a greatsword (4d6 + Str*2 + Rage*2) to two-weapon fighting with handaxes (3d6 + Str*2 + Rage*3), the difference in damage is the difference between 1d6 for the greatsword attacks and one application of your Rage bonus with the handaxes. The rage bonus scales very slowly, so the greatsword attacks have a very minor advantage (1.5 average damage initially), but compare that to the benefits of a +2 AC bonus. Plus, once you get Extra Attack you can do handaxe+handaxe+longsword+shield and reduce that damage gap to just 0.5 average damage. There’s an action economy cost to doing this, of course, but if you weren’t consistently using your Bonus Action already this could be great.
If you insist on playing a martial bard (College of Swords or College of Valor), the Thri-Kreen is a great option. 13+Dex AC helps with your durability problems, and extra hands mean that you can more easily juggle your weapon, your instrument, and possibly a shield if you’re proficient.
For other bards, there’s not much here except Chameleon Carapace.
Most clerics will be at their best with a shield that has their holy symbol on it and and empty hand since weapons are generally a poor choice compared to spells.
Trickery clerics looking to fill in for a rogue may find Chameleon Carapace helpful, but I don’t think it’s enough to make the build effective.
Much like the Cleric, the Druid benefits very little from the Thri-Kreen’s additional hands. Chameleon Carapace is a helpful boost to the Druid’s AC issues, but 13+Dex still isn’t amazing unless you invest heavily in Dexterity. Chameleon Carapace’s benefits to Stealth are similarly helpful, but not amazing, and you’ll likely be better served by turning into an animal when you need to be sneaky.
For a two-weapon fighting build, it’s basically impossible to beat the Thri-Kreen thanks to Secondary Arms. A dexterity-based build will have more AC than comparable fighters due to Chameleon Carapace, and that’s before the possibility of a shield.
If you’re consider the Dual Wielder feat, remember that you only get the +1 AC bonus with a weapon in each hand (not in two hands), so a you can’t stack it with a shield.
Fighters have plenty of room for feats, so, for any melee build, strongly consider Sentinel with a whip in one of your primary hands. Even if you never attack with it during your turn, the ability to stop foes with an Opportunity Attack using either your 10-foot reach (with the whip) or your 5-foot reach (anything else) allows a wonderful tactical decision point about where to halt your enemies’ movement.
Chameleon Carapace is basically the only useful thing that the Thri-Kreen brings to monk.
Similar to the Fighter, but without Fighting Style (Two-Weapon Fighting) and without abundant space for feats, the benefits of Secondary Arms are fairly minor. Once you get Improved Divine Smite, TWF provides another chance to apply the bonus smite damage, but even then it’s not amazing.
For a two-weapon fighting build, it’s basically impossible to beat the Thri-Kreen thanks to Secondary Arms. A dexterity-based build will have more AC than similarly-built rangers due to Chameleon Carapace, and that’s before the possibility of a shield. For subclasses which don’t heavily use their Bonus Action, that’s excellent.
Chameleon Carapace’s Stealth benefits are great if you’re serving as your party’s Scout, but remember that they only apply to hiding, not to moving silently or anything else.
Many rogues enjoy two-weapon fighting, but it’s not so crucial to the Rogue’s tactics that Secondary Arms makes an impact. Rogues also don’t get proficiency with shields so the benefits are extremely minor. Chameleon Carapace helps with both AC and Stealth, but it’s not going to make your build stunningly effective on its own. If you enjoy using Stealth in combat, Chameleon Carapace coupled with Expertise will make that tactic much more reliable.
Cast Mage Armor for the AC and Invisibility when you need to be sneaky.
You already get light armor, so Chameleon Carapace isn’t a huge upgrade.
Cast Mage Armor for the AC and Invisibility when you need to be sneaky.