There is a ton of different homebrew classes that have been constructed for campaigns or characters alike. Matthew Mercer, a Dungeons & Dragons book author, is likely the most likely source of “official homebrew” that you can ask for. He has constructed a monk of the Cobalt Soul, an organization dedicated to knowledge and documentation. Their Monks use research and well-timed blows to bring their enemies to their knees. Do the mechanics match the flavor? Find out in our Way of the Cobalt Soul Monk guide.

Know Thy Enemy: Cobalt Soul Monk 5E

The Monk of the Cobalt Soul is designed to be used in Critical Role campaigns, and for fans of Critical Role. It is by no means an official archetype. Your DM’s permission is required before you select this class. However, this monk archetype can easily be reflavored to better fit any campaign; none of the qualities of this archetype require a Cobalt Soul Library or Repository in any stretch. You can just be a monk who can read their enemies flawlessly.

As a side note, we will be using the version of the Cobalt Soul Monk currently on DnDBeyond.

The Cobalt Soul Monk prioritizes information and gathering data on your enemies before delivering big hits. For parties with lower intelligence, this can be a good way to avoid metagaming and take advantage of vulnerabilities. However, the Cobalt Soul is not without its limits. You’re reliant on being attacked if you want to reach the damage of some other Monk archetypes, which the Monk can only survive so much of. At high levels, it can be a good setup character with a high-damage spell combo.

Extract Aspects

To start, at level 3, you gain additional utility with Flurry of Blows.

Whenever you hit a creature with one of the attacks granted by your Flurry of Blows, you mark them as analyzed. Whenever an analyzed creature misses you with an attack, you can immediately use your reaction to make an unarmed melee attack against that creature. This benefit lasts until you finish a short or long rest.

In addition, you learn the following attributes about the target: Damage Vulnerabilities, Damage Resistances, Damage Immunities, and Condition Immunities.

Let’s be optimistic and say that you are always targeted by your specific analyzed target, and they always miss once. Then this says you can make another attack every round against a specific target that you Flurried. That’s legitimately fantastic, especially since you can flurry another target and have both of them be analyzed.

Now, would a DM say that the analyzed creature understands that you’ve analyzed them, and avoid hitting you? It might make sense, especially for an intelligent combatant. That reduces the utility of this ability. In addition, this still expends your reaction, so you can’t get multiple attacks on multiple targets for multiple misses. Even with that caveat, as a melee character, you’re fairly likely to be targeted. That’s extra damage! Just be careful of your health.

Learning about vulnerabilities, resistances, and immunities is very helpful. You don’t need to spend valuable time researching your target; you can beat them up instead! This does mean that your Sorcerer might want to wait for you to attack before blowing their huge spells on the enemy. Make sure your Cobalt Soul is vocal and willing to spread knowledge to their allies! That’ll boost your effectiveness a lot.

Extort Truth

At level 6, you get some weird utility.

If you hit a creature with an unarmed attack, you can spend 1 ki point to force them to make a Charisma saving throw. On a failed save, the creature is unable to speak a deliberate lie and all Charisma checks directed at the creature are made with advantage for up to 10 minutes. You know if they succeeded or failed on their saving throw.

An affected creature is aware of the effect and can thus avoid answering questions to which it would normally respond with a lie. Such a creature can be evasive in its answers as long as the effect lasts.

A single-target Zone of Truth effect. That’s nice, though I feel like it’s slightly out-of-flavor for it to prevent lies. You hit a nerve cluster, so surely they’d just be woozy, right? And they’re aware that you hit a nerve cluster that cut off their abilities to tell lies?

Still, no matter my gripes with the flavor, you get some good interrogation here. Throw your bard at the issue, and you’ve just become an extra D20 for them to use. And you know that they can’t succeed at a Deception check, no matter what. That can make for awesome scenes of you trying to work around your opponent’s intellect.

This is more of a safety measure than anything else. Spending 1 Ki point on Zone of Truth is really nice, since it’s so niche. A shame that you basically have Zone of Truth “permanently” but… Hey, it comes in handy.

Mystical Erudition

Thankfully, Zone of Truth isn’t the only thing you get at level 6! You also get this!

You learn one language of your choice, and you gain proficiency with one of the following skills of your choice: Arcana, History, Investigation, Nature, and Religion. If you already have proficiency in one of the listed skills, you can instead choose to double your proficiency bonus for any ability check you make that uses the chosen proficiency.

You gain an additional language and an additional skill proficiency from the above list (with the ability to double the bonus of an existing proficiency from the list) at 11th and 17th level.

More utility, but this might be more traditionally easy to use. You’re giving Monks extra languages, making them good translators. The Language boon kinda… Falls flat at level 13. So you’re basically getting 2 Languages before you gain Tongues permanently. If only this helped you talk with people of those languages… Oh well! It’s still nice, especially for races that have trouble scraping together languages early on. Now your Wood Elf can talk to Gnomes without sacrificing everything they know and love.

If that wasn’t enough (and it really wasn’t!), you can get an Expertise effect! That’s spicy! However, you’re locked to Intelligence checks. If you’re playing with Standard Array or Point Buy, then your Monk has awful Intelligence, naturally. You’re too reliant on Dexterity, Constitution, and Wisdom to spread your wings too far. 

So, doubling your Proficiency bonus allows you to instead be really good at those checks! It won’t be overkill, and you’ll still have a chance to fail. But you’ll actually give your traditional Wizard or Artificer a run for their money. That’s legitimately great, and rare for a Monk archetype.

Mind of Mercury

Your brain is growing larger and larger. And now, you’re getting the mechanical benefit of it!

Starting at 11th level, you’ve honed your awareness and reflexes through mental aptitude and pattern recognition. Once per turn, if you’ve already taken your reaction, you may spend 1 ki point to take an additional reaction.

Oh, hmm. That’s good. That’s really good.

So, let’s talk about what reactions a Monk has for themselves. You have Opportunity Attack, Deflect Missiles, Slow Fall, and Extract Aspect’s extra attack. That’s a wide selection of options, and all of them really good to spend your reaction on. 

So you can, at your leisure, spend a Ki Point to swing again, or catch yourself from a fall, or catch an arrow. That can take your enemies (and DM) by surprise, and ups your damage output from Extract Aspect to two possible punches.

That’s good damage. Monk is normally not an obvious choice for Sentinel, but you get the opportunity to swing twice per turn. That can be really annoying for your DM. And, when the enemy swings at you for interrupting your move, and they potentially miss? That’s a punching!

This is really awesome, and is only held back by the once per turn limitation. That’s a much-needed limit, however.

Debilitating Barrage

The final ability that the Cobalt Soul teaches their monks is a gnarly one.

Upon reaching 17th level, you’ve gained the knowledge to temporarily lower a creature’s fortitude by striking a series of pressure points. Whenever you hit a creature with one of the attacks granted by your Flurry of Blows, you can spend 3 ki points to cause the creature to suffer a vulnerability to a damage type of your choice for 1 minute, or until they take damage of that type. A creature who is affected by this feature cannot be affected by it again for 24 hours.

Well, okay, only gnarly with some planning.

To best use this ability, you’re going to want to avoid giving them Vulnerability to Bludgeoning, or whatever damage type you deal. Your punches hurt, but they don’t hurt nearly as hard as other classes; your damage potential is through many different punches.

The best way you can set this up is based on your classes at your disposal. Hopefully, you have a Rogue on your team. Sneak Attack is a great way to detonate this ability consistently, since Rogues have a few ways to get Advantage on it. 

Otherwise, you’ve got yourself some casters (I hope) who can deal more damage than a punch. Prepare Necrotic vulnerability to nuke enemies with spells like Harm, or Force damage for Disintegrate. Then, your Caster follows up and blows the enemy out of existence.

This is limited by Ki point expenditure (which is just not a problem at all, really), the 24 hour limit (which also doesn’t matter too much, but can hurt for spongey bosses), and your party composition. Oh, and you might want to check for Immunity before you use this ability, with Extract Aspects. Otherwise, you might be in for a rude surprise.

Do talk to your DM about if you get the benefits of Extract Aspects before you have to spend the Ki on this ability. That might affect how dangerous this ability can really get, if you don’t have to wait a round for the guaranteed atom bomb!

Best Races for Cobalt Soul Monks

While the Monk is given abilities that focus on Intelligence skills, they are not necessarily looking for Intelligence. You’re still a Monk at the end of the day, and that means you need to be wise, and punch hard!

Variant Human

Ugh, that’s boring! Variant Human offers a ton to any class, but here it feels quite apt. You get your +1 to Dexterity and Wisdom, which is wonderful. Then, you get your early Feat. That feat can be Toughness to boost durability, or Sentinel, to eventually make use of your level 11 ability. That greatly improves your battlefield presence, and makes you a big threat. Then, Skills gives you one more Intelligence skill, just to make you that much better when you reach level 6. That’s great!

Alternatively, Base Human actually gives a surprisingly useful +1 to all stats.

Pallid Elf

One of the characters from the Explorer’s Guide to Wildemount, the Pallid Elf has hundreds of years of experience under their belt. That’s great flavor! Then, you can put their Perception, great Investigation and Insight, and various utility abilities to good use. Of great note is sneaking up on somebody with Sleep or Invisibility and then interrogating them with Extort Truth. That can be scary, and probably really stressful to play through. Could be great fun, for a seeker of knowledge!

Conclusion – Our Take on the Cobalt Soul Monk

The Way of the Cobalt Soul has been molded into a solid Monk Archetype. It’s utility is super cool compared to what a Monk normally has access to. However, it comes at the cost of being somewhat situational, and it almost feels reliant on not having an Intelligent character… Despite not being a good replacement for an Intelligent character. Still, this is a perfectly serviceable Monk with some awesome social abilities and surprising damage. Give it a try, the next time you want to play a Truth Seeker character!