I think the Eldritch Knight is actually a great point of comparison to the Rune Knight. 

If the Eldritch Knight is a fighter with just a smattering of Wizard, then it makes sense to think of the Rune Knight as a sort of fighter/artificer subclass. 

But the Rune Knight arguably gets more spell like effects of greater power than the Eldritch Knight. For instance, Rune Knight gets a better version of Enlarge to cast on itself twice at level 3, 4 levels earlier than the Eldritch Knight will get access to 2nd level spells at all. 

And then even the runes that are available at level 3 are potentially stronger than 2nd level spells because of their casting time and lack of concentration requirements, like the Stone Rune being a version of Hold Person cast as a reaction. 

So the Rune Knight gets better versions of 2nd level spells at level 3, one of which is tied to proficiency bonuses for uses, and others that refresh on a short rest. That is terribly potent. 

The one point I would give in the Eldritch Knights favor is versatility in spell choice, but rules as written there isn't really all that much choice. They are mostly locked into weak castings of evocation spells, or the same slate of good abjuration spells. 

Edit: It might even make more sense to think of Rune knight as a fighter/Warlock class, with a limited number of spells and invocations baked in, but all of which are potent and somewhat unique to them. 

Quote from Kaboom979 >>

The only thing I dislike about the Rune Knight is its Runic Shield ability, simply because it seems like it has a "bug." To be more specific, unless you save the ability to be used in a specific circumstance*, then there is always a 5% chance you make things worse for the person being attacked by turning a normal hit into a critical hit. Other than that, I love the flavor and other abilities of the Rune Knight and can mostly overlook the issue I have with its one feature

*if you only ever use Runic Shield to negate critical hits, then there is no chance of making the situation worse for your ally. Chances are, though, you may not get your full use out of the ability every day if you only save it for crits scored on nearby allies. 

That's an interesting point! They should really errata this one from:

Runic Shield

7th-level Rune Knight feature

You learn to invoke your rune magic to protect your allies. 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.

To:

Runic Shield

7th-level Rune Knight feature

You learn to invoke your rune magic to protect your allies. 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 you choose which roll is used.

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.

Quote from Kronzypantz >>

I think the Eldritch Knight is actually a great point of comparison to the Rune Knight. 

If the Eldritch Knight is a fighter with just a smattering of Wizard, then it makes sense to think of the Rune Knight as a sort of fighter/artificer subclass. 

But the Rune Knight arguably gets more spell like effects of greater power than the Eldritch Knight. For instance, Rune Knight gets a better version of Enlarge to cast on itself twice at level 3, 4 levels earlier than the Eldritch Knight will get access to 2nd level spells at all. 

And then even the runes that are available at level 3 are potentially stronger than 2nd level spells because of their casting time and lack of concentration requirements, like the Stone Rune being a version of Hold Person cast as a reaction. 

So the Rune Knight gets better versions of 2nd level spells at level 3, one of which is tied to proficiency bonuses for uses, and others that refresh on a short rest. That is terribly potent. 

The one point I would give in the Eldritch Knights favor is versatility in spell choice, but rules as written there isn't really all that much choice. They are mostly locked into weak castings of evocation spells, or the same slate of good abjuration spells. 

Edit: It might even make more sense to think of Rune knight as a fighter/Warlock class, with a limited number of spells and invocations baked in, but all of which are potent and somewhat unique to them. 

The incapacitated condition is far less powerful than the paralyzed condition. The paralyzed condition is the incapacitated condition plus some really dire add-ons.

Still, Hold Person only works on humanoids and that severely limits it. I would say since the stone rune ability works on all creatures, the power level is approximately equal so your point stands. This would be a great second level spell to add to the list--- "Incapacitate Monster" :)

Paralyzed

• A paralyzed creature is incapacitated (see the condition) and can't move or speak.
• The creature automatically fails Strength and Dexterity saving throws. Attack rolls against the creature have advantage.
• Any attack that hits the creature is a critical hit if the attacker is within 5 feet of the creature.

Yeah, there was a whole thread on it not long ago... there wasn't exactly a consensus reached, but you can make a strong argument that Runic Shield is a decent 'press your luck' mechanic that can be used on offense or defense, but it's mis-packaged as a purely defensive ability

Quote from AntonSirius >>

Yeah, there was a whole thread on it not long ago... there wasn't exactly a consensus reached, but you can make a strong argument that Runic Shield is a decent 'press your luck' mechanic that can be used on offense or defense, but it's mis-packaged as a purely defensive ability

Interesting!  "Another creature" does include enemy creatures (offense). The problem is you can only use this ability on a hit, so rerolling would be a bad thing.

Runic Shield

At 7th level, you learn to invoke your rune magic to protect your allies. 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.

Quote from SeanJP >>

Quote from Kronzypantz >>

I think the Eldritch Knight is actually a great point of comparison to the Rune Knight. 

If the Eldritch Knight is a fighter with just a smattering of Wizard, then it makes sense to think of the Rune Knight as a sort of fighter/artificer subclass. 

But the Rune Knight arguably gets more spell like effects of greater power than the Eldritch Knight. For instance, Rune Knight gets a better version of Enlarge to cast on itself twice at level 3, 4 levels earlier than the Eldritch Knight will get access to 2nd level spells at all. 

And then even the runes that are available at level 3 are potentially stronger than 2nd level spells because of their casting time and lack of concentration requirements, like the Stone Rune being a version of Hold Person cast as a reaction. 

So the Rune Knight gets better versions of 2nd level spells at level 3, one of which is tied to proficiency bonuses for uses, and others that refresh on a short rest. That is terribly potent. 

The one point I would give in the Eldritch Knights favor is versatility in spell choice, but rules as written there isn't really all that much choice. They are mostly locked into weak castings of evocation spells, or the same slate of good abjuration spells. 

Edit: It might even make more sense to think of Rune knight as a fighter/Warlock class, with a limited number of spells and invocations baked in, but all of which are potent and somewhat unique to them. 

The incapacitated condition is far less powerful than the paralyzed condition. The paralyzed condition is the incapacitated condition plus some really dire add-ons.

Still, Hold Person only works on humanoids and that severely limits it. I would say since the stone rune ability works on all creatures, the power level is approximately equal so your point stands. This would be a great second level spell to add to the list--- "Incapacitate Monster" :)

 

Paralyzed

• A paralyzed creature is incapacitated (see the condition) and can't move or speak.
• The creature automatically fails Strength and Dexterity saving throws. Attack rolls against the creature have advantage.
• Any attack that hits the creature is a critical hit if the attacker is within 5 feet of the creature.

 True, paralyzed is better, but you are still getting to do this as a concentration free reaction spell using Con as your spellcasting stat rather than int.

So arguably still better, since you still get to attack on your turn and you don't lose concentration be getting poked (2 of the greatest shortcomings of the Hold spells). 

Quote from Kronzypantz >>

True, paralyzed is better, but you are still getting to do this as a concentration free reaction spell using Con as your spellcasting stat rather than int.

So arguably still better, since you still get to attack on your turn and you don't lose concentration be getting poked (2 of the greatest shortcomings of the Hold spells). 

Yeah, true. No concentration plus applies to any creature... arguably even better than the Hold Person spell overall.

Quote from Torvald99 >>

 Not seeing this one.  

You get advantage whenever you want it...as long as you only want it three times a day.  You have to get to 10th level to get it once more, every time you roll initiative.  So you will have it once per fight, at minimum.  That part is ok, but certainly not spectacular.  Advantage for one turn isn't really all that much imo.  

Proficiency in Wisdom saves is nice and situationally useful.  It does give you a free Res (Wis) feat, essentially.  But probably not crucial at level 7, better if your game goes into the teens.  I only have a +1 to Wis on my fighter/barbarian in an Icewind Dale campaign and the other fighter is -1 Wis.  We have only had to make a few Wis saves, so far.  So it really hasn't been an issue in Icewind Dale. 

Rapid Strike is nice and a good trade off.  An extra attack is easily more valuable than making an attack with advantage.  This is the strongest ability I have seen from Samurai.  At 15th level, you would have 3 attacks already and can make a 4th with this ability.  Throw in duel wield or polearm master and you get 5 attacks!  Pretty strong.  

Strength before Death is basically just spitting in their eye on your way out! ;) 

I think a lot of the strengths of your character are your magic items and build, not the strengths of the class itself.  You may love your character, but maxing out Dex, then getting a storm giant belt would be insane for ANY fighter class, not just a samurai. :) 

Here's the way I see things: The more a character is able to free up what are considered "must haves" in a build, the more freedom of choice you're given when building it.

I really like that the samurai comes prepackaged with a way to use up its bonus action in a significant way to optimize damage. I don't need to take PAM. I like the rune knight for similar reasons, although their bonus action is just used for other purposes. Now, while your DM may not utilize wisdom saving throws often in your particular campaign, I play in AL in tier 4, where wisdom saving throws are common and they're no joke. A fighter at that level is heavily penalized if they fail, so it's a very common suggestion and considered a "must have." 

Even if another fighter copied my build in stats and items, they'd be "two feats behind" so to speak. It's like the samurai has two MORE feats, and it's for that reason, among others, that makes a fighter special among the other martials. This opens up the possibilities like taking more defensive feats. I could take lucky, so not only do I have proficiency in wisdom saving throws, but I also have indomitable, and I also have three luck points a day. That's insane. I could take alert, thereby boosting my high initiative even higher. 

Now, because I play mostly through AL modules, where adventures are self-contained within a four hour span, 3 times a day is plenty enough for me. In general, advantage is an easy thing to acquire for other classes, but when it comes to fighters, the samurai is the only one who can generate it as easily as they can. 

Also, I know I've brought this up in the past, but I've got my own anecdotal evidence/bias as to why I like the samurai. My buddy won a battle royale styled pvp tournament at his local game store where everyone brought their AL characters, we're talking lvl 20 wizards and moon druids and sorcadins galore. All those guys were optimizers, min-maxers. He played a samurai AND WON! 'Nuff said. 

Quote from SeanJP>>

Quote from AntonSirius>>

Yeah, there was a whole thread on it not long ago... there wasn't exactly a consensus reached, but you can make a strong argument that Runic Shield is a decent 'press your luck' mechanic that can be used on offense or defense, but it's mis-packaged as a purely defensive ability

Interesting!  "Another creature" does include enemy creatures (offense). The problem is you can only use this ability on a hit, so rerolling would be a bad thing.

 There are, admittedly rare, circumstances where you might be fishing for crits, and getting a normal hit wouldn't really matter that much

One small thing nobody's mentioned yet is that a large creature can use a two handed weapon in one hand.  So when you go big, a Rune Knight could use 2 two handed swords, etc.

Quote from Barazinbar >>

One small thing nobody's mentioned yet is that a large creature can use a two handed weapon in one hand.  So when you go big, a Rune Knight could use 2 two handed swords, etc.

 Not doubting you, but where can I find that in the rule book?

I thought for sure I saw it in the rules somewhere.  it could be I'm remembering that from another version of D&D.  I did find this in the DMG under creating a monster: 

If a monster wields a manufactured weapon, it deals damage appropriate to the weapon. For example, a greataxe in the hands of a Medium monster deals 1d12 slashing damage plus the monster’s Strength modifier, as is normal for that weapon.

Big monsters typically wield oversized weapons that deal extra dice of damage on a hit. Double the weapon dice if the creature is Large, triple the weapon dice if it’s Huge, and quadruple the weapon dice if it’s Gargantuan. For example, a Huge giant wielding an appropriately sized greataxe deals 3d12 slashing damage (plus its Strength bonus), instead of the normal 1d12.

A creature has disadvantage on attack rolls with a weapon that is sized for a larger attacker. You can rule that a weapon sized for an attacker two or more sizes larger is too big for the creature to use at all.

I did some searching. It appears that used to be a thing in an earlier version (or perhaps more than one earlier version). But 5E goes out of its way not to allow that. I big into optimizing, and if that was an option with spells like Enlarge/Reduce I likely would have heard of it. That would be pretty sick if you could. Be a sword and board rune knight.

2d6 and +2 damage from Dueling fighting style.

As a DM I would allow it.  I think it makes sense. I think that's one reason you won't find a single PC race that's large.  There are definitely some races that are awfully close (Goliath and Formorian).  

Quote from Barazinbar >>

As a DM I would allow it.  I think it makes sense. I think that's one reason you won't find a single PC race that's large.  There are definitely some races that are awfully close (Goliath and Formorian).  

 Yeah, the developers are always having to walk the tight rope between the game being balanced and realistic. That would be really powerful. I think the +1d6 for Giant’s Might it’s supposed to account for the larger weapon. 

I do think for both, Giant’s Might and the Enlarge/Reduce spell they should grant +5 reach. If they did just that it would make it much more realistic, and I don’t think it would imbalance it.

I would hazard the beauty of the Rune Knight is that it has versatility, built on a sturdy foundation.

At it's core, you become a hulking brute...but you also have a tool for nearly any situation.

With their bag of tricks, they contribute to combat with steady damage, but also support for their party...and the bonus action & reaction economy keeps everything running very smoothly.

It's just a very reliable, very solid subclass...that I now want to play again.

I do sort of miss the "Giant Soul" Sorcerer subclass that came out in prior Unearthed Arcana...it nicely highlighted the "magic" of the giants...but I ultimately am grateful that we got this truly unique Fighter subclass.

Quote from Barazinbar >>

One small thing nobody's mentioned yet is that a large creature can use a two handed weapon in one hand.  So when you go big, a Rune Knight could use 2 two handed swords, etc.

You didn't stumble onto my large player races homebrew by any chance? Or somewhere I was discussing it (I recently mentioned it on the article about the Fairy race where people were complaining about not having Tiny or Large playable races)?

For those races I allow basically this, but it's a racial feature not something inherent to the size. There's also the note in the DMG (p275) about creating monsters, and how you might double weapon dice for larger sizes, but that's for building monster stat blocks and not really intended as a general "being Large means double dice" feature.

Quote from SeanJP >>

I do think for both, Giant’s Might and the Enlarge/Reduce spell they should grant +5 reach. If they did just that it would make it much more realistic, and I don’t think it would imbalance it.

You already kind of are; being Large means you now control a 10 foot square so you can reach enemies without moving that a smaller character couldn't, this is also an area larger than your character actually occupies. Just as a Medium sized creature doesn't fully occupy a five foot square (not without a far too low power stance anyway) your average large creature won't fill that space, it's just their area of control (or vulnerability, for effect areas etc.).

Adding reach would mean a larger target is suddenly able to avoid attacks of opportunity which would be a bit weird IMO, as if anything you're preventing more of a target when you try to move away.