Rune Knight Fighter Subclass Guide

Last Updated on November 29, 2023

Rune Knights are a Fighter Subclass characterized by their ability to wield supernatural runes.  This first section is everything unique to the Rune Knight.  

Below that we explain how to use these abilities effectively.  Then take you through your options for character creation and Rune Knight builds.

Rune Knight Fighters

Rune Knights enhance their martial prowess using the supernatural power of runes, an ancient practice that originated with giants. Rune cutters can be found among any family of giants, and you likely learned your methods first or second hand from such a mystical artisan. 

Whether you found the giant’s work carved into a hill or cave, learned of the runes from a sage, or met the giant in person, you studied the giant’s craft and learned how to apply magic runes to empower your equipment.

Source:  Tasha’s Cauldron of Everything

Bonus Proficiencies: 

You gain proficiency with smith’s tools and learn how to speak, read, and write Giant.

Rune Carver: 

You learn two runes of your choice from among the runes available to this subclass. Each time you gain a level, you can replace a rune you know with a different one from this feature. At certain levels shown in the table below, you learn additional runes.

Whenever you finish a long rest, you can touch a number of objects equal to the number of runes you know and inscribe a different rune on each. The object must be something you can wear or hold in a hand. The rune remains until you finish a long rest, and an object can only have one rune at a time.

If a rune requires a saving throw, the DC is equal to 8 + your proficiency bonus + your Constitution modifier. 

Below is the list of runes available to you as written in Tasha’s Cauldron of Everything.

  • Cloud Rune. This rune emulates the deceptive magic used by some cloud giants. While wearing or carrying an object inscribed with this rune, you have advantage on Dexterity (Sleight of Hand) checks and Charisma (Deception) checks.
    • In addition, when you or a creature you can see within 30 feet of you is hit by an attack roll, you can use your reaction to invoke the rune and choose a different creature within 30 feet of you other than the attacker. The chosen creature becomes the target of the attack, using the same roll. This magic can transfer the attack’s effects regardless of the attack’s range. Once you invoke this rune, you can’t do so again until you finish a short or long rest.
  • Fire Rune. This rune’s magic channels the masterful craftsmanship of great smiths. While wearing or carrying an object inscribed with this rune, your proficiency bonus is doubled for any ability check you make that uses your proficiency with a tool.
    • In addition, when you hit a creature with an attack using a weapon, you can invoke the rune to summon fiery shackles: the target takes an extra 2d6 fire damage, and it must succeed on a Strength saving throw or be restrained for 1 minute. While restrained by the shackles, the target takes 2d6 fire damage at the start of each of its turns. The target can repeat the saving throw at the end of each of its turns, banishing the shackles on a success. Once you invoke this rune, you can’t do so again until you finish a short or long rest.
  • Frost Rune. This rune’s magic evokes the might of those who survive in the wintry wilderness, such as frost giants. While wearing or carrying an object inscribed with this rune, you have advantage on Wisdom (Animal Handling) checks and Charisma (Intimidation) checks.
    • In addition, you can invoke the rune as a bonus action to increase your sturdiness. For 10 minutes, you gain a +2 bonus to all ability checks and saving throws that use Strength or Constitution. Once you invoke this rune, you can’t do so again until you finish a short or long rest.
  • Stone Rune. This rune’s magic channels the judiciousness associated with stone giants. While wearing or carrying an object inscribed with this rune, you have advantage on Wisdom (Insight) checks, and you have darkvision out to a range of 120 feet.
    • In addition, when a creature you can see ends its turn within 30 feet of you, you can use your reaction to invoke the rune and force the creature to make a Wisdom saving throw. Unless the save succeeds, the creature is charmed by you for 1 minute. While charmed in this way, the creature has a speed of 0 and is incapacitated, descending into a dreamy stupor. The creature repeats the saving throw at the end of each of its turns, ending the effect on a success. Once you invoke this rune, you can’t do so again until you finish a short or long rest.
  • Hill Rune (7th Level or Higher). This rune’s magic bestows a resilience reminiscent of a hill giant. While wearing or carrying an object that bears this rune, you have advantage on saving throws against being poisoned, and you have resistance against poison damage.
    • In addition, you can invoke the rune as a bonus action, gaining resistance to bludgeoning, piercing, and slashing damage for 1 minute. Once you invoke this rune, you can’t do so again until you finish a short or long rest.
  • Storm Rune (7th Level or Higher). Using this rune, you can glimpse the future like a storm giant seer. While wearing or carrying an object inscribed with this rune, you have advantage on Intelligence (Arcana) checks, and you can’t be surprised as long as you aren’t incapacitated.
    • In addition, you can invoke the rune as a bonus action to enter a prophetic state for 1 minute or until you’re incapacitated. Until the state ends, when you or another creature you can see within 60 feet of you makes an attack roll, a saving throw, or an ability check, you can use your reaction to cause the roll to have advantage or disadvantage. Once you invoke this rune, you can’t do so again until you finish a short or long rest.

Giant’s Might: 

As a bonus action, you can imbue yourself with the might of giants, entering a form that lasts for 1 minute. During that time, you have the following effects:

  • If you are smaller than Large, you become Large along with anything you are wearing. If you lack the room to become Large, your size doesn’t change.
  • You have advantage on Strength checks and Strength saving throws.
  • Once on each of your turns, one of your attacks with a weapon or an unarmed strike can deal an extra 1d6 damage to a target on a hit.

You can use this feature a number of times equal to your proficiency bonus, and regain all uses on a long rest.

Runic Shield:

When another creature you can see within 60 feet of you is hit by an attack roll, you can use your reaction to force the attacker to reroll the d20 and use the new roll. You can use this feature a number of times equal to your proficiency bonus, and you regain all expended uses when you finish a long rest.

Great Stature: 

When you gain this feature roll 3d4, you grow a number of inches in height equal to the roll. Additionally, the extra damage you deal with your Giant’s Might increases to 1d8.

The height is basically a nonissue, but it’s a nice bit of flavor. Technically, this could put some creatures into the next size category though, so make sure you know your height going into this build. 

The real draw is obviously the extra damage, and trust me, bumping up to 1d8 from 1d6 is going to make a difference.

Master of Runes: 

You can now invoke the activated abilities of each of your runes twice rather than once before you need to replenish on a short or long rest.

Runic Juggernaut: 

The extra damage you deal with the Giant’s Might feature increases to 1d10. Additionally, when you use that feature, your size can increase to Huge, and while you are that size, your reach increases by 5 feet.

Rune Knight Class-Defining Abilities

  • Runes
  • Giant Form
  • Double-down features

Runes

Whenever a Rune Knight finishes a long rest, they can inscribe a number of runes onto different objects that are worn or carried (weapon, suit of armor, shield, jewelry, etc.). 

You must inscribe a different rune on each object, and an object can only hold a single rune at a time.

Some runes require creatures to make saving throws. In those cases, the save DC equals 8 + your proficiency bonus + your Constitution modifier.

There are only six total runes, so I’ll explain what each does and how beneficial each is. In general though, each rune has a passive effect and an activated ability. Additionally, you must finish a short or long rest before you can use the activated ability again.

The Six Runes of the Rune Knights – Explained

Cloud Rune

This rune gives you advantage on Sleight of Hand (Dexterity) and Deception (Charisma) checks. 

Additionally, when you or a creature within 30 feet of you is hit by an attack roll, you can use your reaction to choose a different creature within 30 feet of you, other than the attacker, to receive the effects of the attack.

It passively gives you great bonuses for social interactions since both sleight of hand and deception are skills you can choose to use at just about any time. 

The activated ability definitely makes this a powerful contender for the best rune though since you’re automatically transferring the effects of an attack to a new target without even having to worry about a saving throw. 

This can save you or an ally from death, be the perfect finishing touch on a strong enemy, or possibly even both.

Fire Rune

While wearing or holding this rune, your proficiency bonus is doubled for any ability checks you make with tools that you are proficient in. 

The activated ability provides a bonus effect when you hit a creature with a weapon attack. If you choose to invoke the rune, you deal an extra 2d6 fire damage to the target, and they must succeed a Strength saving throw or be restrained for 1 minute.

 While restrained, they take 2d6 fire damage at the start of each of their turns and can repeat the saving throw at the end of each of their turns, ending the effects on a success.

To double your proficiency bonus with tools is an incredible bonus and can let you put some serious thought into which tool proficiencies you might want to pick up.

At the very least, you’ll be getting smiths’ tools as a bonus proficiency from this subclass, and anything else is a bonus.

Then, dealing extra damage, potentially 32d6 of it, is absolutely incredible. Dishing out even just 2d6 of damage at lower levels is a big bonus, and this ability continues to be beneficial throughout a campaign.

Frost Rune

Your passive ability gives you advantage on Animal Handling (Wisdom) and Intimidation (Charisma) checks.

The activated gives you a +2 bonus to all ability checks and saving throws that use Strength and Constitution. This effect is activated as a bonus action and lasts for a whopping 10 minutes. 

While Intimidation checks and a bonus to rolls are great, this ability does feel a bit lacking. This is mainly because the activated bonus won’t affect your attack rolls, which limits us to outside of combat or in combat and hoping that we end up making STR or CON saves.

Altogether, this is definitely beneficial, but it could certainly be improved if it wants to compete on the same level as the other runes we have access to.

Stone Rune

The stone rune gives its user advantage on Insight (wisdom) checks and darkvision out to a range of 120 feet.

When a creature ends its turn within 30 feet of you, you can use your reaction to force the creature to make a Wisdom saving throw. Unless the save succeeds, the creature is charmed by you for 1 minute. For the duration of the charm, the creature has a speed of 0 and is incapacitated. They can repeat the save at the end of each of their turns, ending the charm on a success.

The stone rune is really interesting and provides some serious variety of effects. Insight is great for social interaction, such a wide range of darkvision is great for exploration and combat, and the charm is obviously a huge boon in combat. Put these together, and you have probably the most well-rounded rune of the starting four. 

Hill Rune

In order to learn this rune, you must be level 7 or higher. 

The passive ability of this rune gives you advantage on saving throws against being poisoned and resistance to poison damage. The activated ability lets you use a bonus action to gain resistance to bludgeoning, slashing, and piercing damage for a minute.

For a rune with a level prerequisite, this is honestly a bit lackluster. Now, I need to be clear: These abilities are absolutely excellent; it’s just that they’re easily accessible. If you really want these abilities, you could choose dwarf as your race, since dwarven resilience gives you the same exact mechanical benefits as the passive ability. 

Then, and this is a bit harder to justify, you could get access to the activated ability and more by taking a single level dip into barbarian for their rage feature. Just doing that would give you those resistances twice a day along with bonus damage on attacks and a myriad of other benefits.

So, is this a good rune to choose? Yes, of course it is. These provide you some excellent resistances and ways to avoid taking some serious harm. Is it necessary? No, you could easily get all of the benefits of this rune at a much earlier level without having to choose it as one of your runes.

Storm Rune

In order to learn this rune, you must be level 7 or higher. 

This rune’s passive ability gives you advantage on Arcana (Intelligence) checks and prevents you from being surprised so long as you aren’t incapacitated.

The activated ability of the storm rune allows you to enter a 1-minute prophetic state through the use of a bonus action. For the duration, whenever you or another creature you can see within 60 feet of you makes an attack roll, saving throw, or ability check, you can use your reaction to cause the roll to have advantage or disadvantage. 

This rune is incredible. The only thing that could make it better is swapping out arcana for perception, but we’ll take it as it can still definitely be used as a handy skill check. 

The main benefit of the passive ability is definitely the surprise prevention, which kind of makes perception a nonissue as long as you don’t find yourself incapacitated.

Then, this really shines when you activate the prophetic state and start controlling the rolls of you and your allies like you were some sort of RNG god.

If you compare this to other roll-control abilities, this is probably one of the most powerful in the game. It certainly rivals the oft-lauded Portent ability of the divination wizard, and that lets you actually replace two of the same types of rolls each day. 

Giant Form 

This form is huge, get it? Seriously though, this feature is probably what saves this subclass from being mediocre. 

Since you can reliably activate this for almost every combat you enter, you can just about guarantee that you’ll be dealing extra damage on your attacks.

I’m not just talking about that wimpy d6 either. Since your equipment all becomes large as well, you’ll have a large weapon, which means doubling the dice you use when calculating damage. 

So for a Greataxe, that’s 2d10 instead of 1d10 and an extra 1d6 every turn. This is essentially doubling the amount of attacks you get in a turn.

Combat is obviously the main thing we want to focus on as a fighter, but the strength advantage and increased carrying capacity can have some impressive limitations when we’re exploring as well. 

Use this feature wisely, and you’ll feel not only like you are a giant but like you could easily fell one if push came to shove.

Ability Scores for a Rune Knight

When building a character, we start by figuring out which ability scores to focus on. For a Rune Knight, that’s going to be strength and constitution without a doubt. 

While most fighters can use strength or dexterity interchangeably, the focus on strength and size we see in this class just further locks us into melee strength-based combat.

Below I’ve listed each ability score and just how important it is to this subclass.

Primary: Strength 

Tier II: Constitution 

Tier III: Dexterity, Wisdom, Charisma

Dump Tier: Intelligence

Strength: The most important stat. This rules our ability and combat and also determines how much use we’ll get out of all the bonuses to strength checks and saving throws that we’ll get. With a bad strength score, even great bonuses can’t make much of a difference.

Dexterity: While we won’t be using this for much, it’s still incredibly important that we have a decent dexterity score so that our AC can justify us being on the front lines of battle.

Constitution: Not only does Constitution determine our hit points, but it also affects our runic save DC, something we’ll want to ensure is high if we want to have any chance of using them on our enemies.

Intelligence: We may want this if we choose to focus on arcana checks like our Storm Rune might suggest, but otherwise, we will almost never need this to be above 10.

Wisdom: Wisdom is useful for insight, perception, and more, and can be great for just generally discerning information. This is a solid competitor for our 4th-place score, although it might lose out to the next ability in some builds.

Charisma: There are two runes that give us advantage on a charisma-based skill, so if we want to reliably use deception or intimidation, this is the score to put points in so that we actually succeed on those checks. It should never go above Dexterity unless we want to multiclass, but in general, it’s a great contender for 4th place.

Our Race Suggestions for your Rune Knight

Mountain Dwarf: +2 Strength and +2 Constitution is the perfect combo for this class and the best ability score increase you’ll find in any 5e race. 

Aside from that, we also get dwarven resilience, which offers the same poison-related benefits as the passive ability of the Hill Rune.

Goliath: +2 Strength and +1 Constitution is a close runner-up to the mountain dwarf. We also get Stone’s Endurance, a feature that lets us reduce incoming damage by 1d12 once before recharging the ability on a short or long rest.

Perhaps most important is the Powerful Build feature that says, “You count as one size larger when determining your carrying capacity and the weight you can push, drag, or lift.” 

This stacks with our giant’s might, so when we’re Large, we’ll count as Huge for carrying purposes, and when we’re Huge, we’ll count as Gargantuan! 

I’m sure you can come up with some incredible uses for this; all it takes is a small bit of creativity. 

Half-Orc: +2 Strength and +1 Constitution. Orcs are one of the few races that are going to give us some serious benefits in combat. 

Their Relentless Endurance is going to have us drop to 1 hit point instead of 0 if we wouldn’t die outright, a trait we can use once a day. 

More importantly, though, Savage Attacks lets us roll one of our weapon’s damage dice an additional time when we score critical hits. With the amount of attacks available to fighters, this is going to stack up to a whole lot of additional damage over time.

Bugbear: Custom ASI. You’ll still want to use the same spread of Ability Score Increases as our other listed races, but you can switch it up if you want to. 

This race offers us the same Powerful Build trait as goliaths along with a collection of other helpful features. 

Long-Limbed increases our melee reach by 5 feet, which will stack with our final version of Giant’s Might for a total +10 ft of reach. Surprise attack lets us deal an extra 2d6 damage if we hit a creature that hasn’t moved yet in combat. 

This won’t trigger often, but it’s a nice chunk of damage to stack on. 

Skill Choices

Fighters choose two skill proficiencies from Acrobatics, Animal Handling, Athletics, History, Insight, Intimidation, Perception, and Survival.

Acrobatics: This is a useful skill, but this subclass is much more focused on sturdiness than nimble movements.

Animal Handling: Animal handling is very campaign dependent. Some campaigns will hardly feature animals that can be handled, making this useless. 

Still, if you’re interested in taking it, you can always mention your interest to your DM in hopes that more opportunities to use it will arise.

Athletics: As the only strength-based skill, this is an important skill for us to choose if we really want to maintain our focus on strength checks. 

History: There isn’t much to suggest that this subclass would be knowledgeable about history, but again, take it if it suits you.

Insight: We can get advantage on insight checks through one of our runes, and it’s a very useful skill in social interaction.

Intimidation: Much like insight, we can get the most benefit from our intimidation rune if we already have proficiency in this skill.

Perception: Proficiency is always a useful skill as it’s one of the few that we use even passively. 

Adding proficiency here can protect us from surprise and give us the upper hand in many different scenarios.

Survival: Leave survival to the rangers and druids. 

Background Choices

Choosing a background is mostly about flavor. 

The suggestions I have here are based more on archetypes than mechanical benefits. In truth, there really are no “optimized” backgrounds.

Gladiator: This background is for someone who wants to embody the fierce combatant spirit of a giant while keeping their character grounded in reality and simultaneously baking in a little bit of fun. 

Hermit/Archaeologist/Anthropologist: Any of these are great backgrounds if you want your character to have stumbled across and studied ancient giant runes to learn the secrets of the runic language. 

This gives a lot of credence to a character having sudden power and learning the ropes of a supernatural power source. 

Rune Knight Fighter Build 

For the following example build, we’ve used the standard set of scores provided in the PHB (15, 14, 13, 12, 10, 8) when deciding ability scores. 

This section will provide you with a collection of the best choices from this article put into a single character build along with explanations of different synergies and a general path for progression. 

  • Race: Bugbear
  • Background: Far Traveler
  • Ability Scores: STR 16,  DEX 13, CON 16, INT 8, WIS 10, CHA 12
  • Skill Proficiencies: Insight, Intimidation, History, Survival
  • Language Proficiencies: Giant, Goblin, Common
  • Tool Proficiencies: Smith’s Tools, Cartographer’s Tools
  • Equipment: Chain mail, glaive, great axe, two handaxes, explorer’s pack, wooden case containing a map to a ruin or dungeon, a bullseye lantern, a miner’s pick, a set of traveler’s clothes, a shovel, a two-person tent, a trinket recovered from a dig site, and a pouch containing 25 gp
  • Fighting Style: Great Weapon Fighting
  • Feats: Great Weapon Master (4th), Sentinel (8th), Polearm Master (10th)

Runes:

  • 3rd Level: Cloud Rune, Fire Rune
  • 7th Level: Storm Rune
  • 10th Level: Hill Rune
  • 15th Level: Stone Rune

This build focuses on making us large and in charge, of the battlefield that is. We’re all about battlefield control, and focusing on reach weapons is an excellent way to do that, especially as we grow in size. 

The final build is a character with a 20-foot reach and a wide range of opportunity attacks that can dish out a load of damage on a single attack if all abilities stack nicely. 

On the rare occasions where that isn’t enough, we have charming abilities and more mystical battlefield control to cover our bases.

You can follow along with the progression your Rune Knight will take below:

Rune Knight Fighter Progression

We start at Character Creation and take you level by level through the choices you will face. 

Filling Out the Character Sheet (Level 0)

  • Hit Dice: 1d10 per Fighter level
  • Hit Points at 1st Level: 10 + your Constitution modifier
  • Hit Points at Higher Levels: 1d10 (or 6) + your Constitution modifier per fighter level after 1st

Proficiencies:

  • Armor: All armor, shields
  • Weapons: Simple weapons, martial weapons
  • Tools: None
  • Saving Throws: Strength, Constitution
  • Skills: Choose two skills from Acrobatics, Animal Handling, Athletics, History, Insight, Intimidation, Perception, and Survival

Equipment:

You start with the following equipment in addition to the equipment granted by your background:

  • (a) chain mail or (b) leather, longbow, and 20 arrows
  • (a) a martial weapon and a shield or (b) two martial weapons
  • (a) a light crossbow and 20 bolts or (b) two handaxes
  • (a) a dungeoneer’s pack or (b) an explorer’s pack

1st Level

Favored Enemy: 

Choose a fighting style from the list below:

  • Archery. 
  • Blind Fighting. 
  • Defense. 
  • Dueling. 
  • Great Weapon Fighting. 
  • Interception. 
  • Protection. 
  • Superior Technique. 
  • Thrown Weapon Fighting. 
  • Two-Weapon Fighting. 
  • Unarmed Fighting.

The best choices in this feature for a rune knight are probably great weapon fighting and superior technique. GWF will greatly increase your damage output while gaining a few battle maneuvers can bring a lot of diversity to this subclass’s abilities.

Second Wind:

On your turn, you can use a bonus action to regain hit points equal to 1d10 + your fighter level. You must finish a short or long rest before you can reuse this feature.

2nd Level

Action Surge:

On your turn, you can take one additional action. Once you use this feature, you must finish a short or long rest before you can use it again. Starting at 17th level, you can use it twice before a rest but only once per turn.

This feature is hugely beneficial and should definitely be used while you have one of your minute-long effects up and running so that you can get the maximum value.

3rd Level

This level you get your initial Rune Knight powers.  They include:

Bonus Proficiencies

Rune Carver (Access to 2 runes at this level)

Giant’s Might

 See the top of the article for details.

4th Level

ASI: 

You can either increase one ability by 2 points or two abilities by 1. Alternatively, you can choose a feature. If you already have great stats this is a great choice.

Martial Versatility (Optional):

Whenever you receive an ASI, you can also choose to do one of the following.

  • You can choose to switch out your fighting style for a different one. 
  • If you know any Battle Master maneuvers, you can replace one you know with a different maneuver.

5th Level

Extra Attack:

Fighters get to make a second attack whenever they take the Attack action as a part of their turn. This increases to three attacks at 11th level and four at 20th level.

6th Level

ASI

7th Level

Runic Shield:

When another creature you can see within 60 feet of you is hit by an attack roll, you can use your reaction to force the attacker to reroll the d20 and use the new roll. You can use this feature a number of times equal to your proficiency bonus, and you regain all expended uses when you finish a long rest.

This is an incredible ability that essentially functions like a soft version of the Storm Rune’s ability. Remember, you only get one reaction per round of combat, so you won’t be using this while your storm rune is activated. 

8th Level

ASI

9th Level

Indomitable:

You can reroll a saving throw that you fail. You must use the new role and can’t use it again until you finish a long rest. You can use this feature twice between long rests starting at 13th level and three times between long rests starting at 17th level.

10th Level

Great Stature: 

When you gain this feature roll 3d4, you grow a number of inches in height equal to the roll. Additionally, the extra damage you deal with your Giant’s Might increases to 1d8.

The height is basically a nonissue, but it’s a nice bit of flavor. Technically, this could put some creatures into the next size category though, so make sure you know your height going into this build. 

The real draw is obviously the extra damage, and trust me, bumping up to 1d8 from 1d6 is going to make a difference.

12th Level

ASI

15th Level

Master of Runes: 

You can now invoke the activated abilities of each of your runes twice rather than once before you need to replenish on a short or long rest.

16th Level

ASI

18th Level

Runic Juggernaut: 

The extra damage you deal with the Giant’s Might feature increases to 1d10. Additionally, when you use that feature, your size can increase to Huge, and while you are that size, your reach increases by 5 feet.

19th Level

ASI

I hope this article has given you everything you need, and as always, happy adventuring.

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