My first attempt at build optimization

[TheHalfAasimar]

So, I've had this build idea for a while, until it finally came to fruition.

For those of you who have XgTE, you know the Samurai fighter. Advantage at will, the whole shcaboodle. And for those of you who have the PHB, you know the Rogue. Extra damage, new DMs nerf it because 'it's too powerful' when it isn't. But I'm not here to make the rogue more powerful, I'm here to maximise damage output from a Samurai fighter.

Step 1:
You take your first level in Fighter. Choose Rapier as your weapon (because Finesse), then choose a race with a +2 DEX bonus. You also must choose the Dueling fighting style (so that you get a +2 damage with a weapon in one hand and nothing else in the other) for the DMG bonus.
Our stats will be as follows, from highest to lowest:
Dex (for Rapier)
Con (for HP)
Wis (for saves + passive perception + samurai stuff)
Str (just in case)
Int (still handy to be smart)
Cha (useless)

At level 2, multiclass into Rogue, take another level, then at level 4 go back to Fighter. When you get to choosing a subclass on Fighter, choose Samurai, and stay that way until you have 17 levels of Fighter. Why? Well, let's break down some of the stuff we get:
We get advantage at will at 3rd level (I think, don't quote me on this) and a bit of Temp. HP. It slowly improves as we level up, to becoming the best it can be at level 15. So why don't we stop there? I'll tell you why we don't stop there. Because, at level 17, fighters now have 4 attacks per turn. Now, at level 10, Samurai get an additional use of Fighting Spirit whenever they roll initiative, but that's far behind us.
Now, once we have 17 levels of Fighter and 2 levels of Rogue, get another level of Rogue. That way, we have 2d6 Sneak Attack dice that trigger on advantage. As for subclass, I don't think 3 levels is going to make much of a difference, unless the enemy is surprised. We choose Assassin for the ability to have advantage on all attack rolls against an enemy, provided they are surprised and haven't taken a turn yet.
So let's look at the bonus to hit:
Is this viable? Well, at this point, if you have a nice DM, you probably have a +3 rapier, max DEX, and a +6 proficiency bonus for a total of...
6+5+3=






14.

+14 to hit. Not bad, I'd say! Now, let's look at the average AC of a CR 20 creature. I didn't have the time to look through both the MM and FToD, so I just turned to the first ~CR20 creature I found, which, conviently, was a Solar, at CR 21.
Now, it's technically DC 7 to hit the Solar, because 7+14 is the bare minimum for whether you hit or not. So, you have a 70% chance to hit the solar.

But wait! We've forgotten something very important: Advantage.
I rolled dice a bunch of times for average Advantage bonus, and it came out to approximately +6. So, 14+6 (from advantage) is +20 technically, so it's DC 1 to hit a Solar. And at that point, getting a Nat 1 was the only thing that could stop you, anyways. Now, if you don't have a +3 rapier, it's DC 4 to hit, and you have about a 75% chance to hit, which, mind you, isn't that bad, but still.

Let's look at the damage:

If we have a +3 Rapier, max DEX, Sneak Attack 2d6, and the Dueling fighting style, let's see:

Assuming we're fighting the aforementioned Solar, we have a 95% chance of hitting each time, but with my luck, that's more like a 50%. But, in the chance we don't roll a single Nat 1, we're good.

Assuming we do the normal Action Surge for 8 attacks, all with advantage, and all of them but 1 hit, that's an average of:

+3 rapier: 1d8 +3, average of 7.5
Max DEX: +5
Sneak attack 2d6: Average of 7

For a grand total of (on average)

7.5+5+7=19.5, which is almost as much as a fireball.
19.5 * 8 (we'll probably hit all the times) = 156, which is more than a fully upcast lvl 9 Fireball, which does 14d6, and assuming it does max damage, and we reroll all 6s for more 6s (with that one Tiefling feat) the max damage for THAT MONSTER is 168, and that's MAXIMUM DAMAGE. Now what about max damage for this? Well, the odds are quite low, but here we go:
8+3+5+12 = 28
28 * 8 = 224.
Keep in mind that the Samurai fighter can do this basically one time per Initiative roll, but on combats 1 and 2 he or she will probably do this multiple times. So, yeah.

Thoughts?

[Elenian]

Sneak attack is once per turn. Also your advantage math is wrong (or, rather, you've gone about it the wrong way) - if you need a 7 to hit with advantage, your odds of missing are (6/20)^2 which is 9%.

Edit: also that's not what Flames of Phlegethos (the 'tiefling feat' I think you're taking about) does.

[TheHalfAasimar]

Sneak attack is once per turn. Also your advantage math is wrong (or, rather, you've gone about it the wrong way) - if you need a 7 to hit with advantage, your odds of missing are (6/20)^2 which is 9%.

Oh. Then the whole thing falls apart. Thanks for pointing that out. But thanks for doing the math, too!

[Unoriginal]

Oh. Then the whole thing falls apart. Thanks for pointing that out. But thanks for doing the math, too!

Samurai Fighter + Rogue is still a very solid build. Not the most common choice for Rogue/Fighter multiclass, but still very solid.

I wouldn't dismiss CHA as useless for that build, either. Samurai/Rogue can be efficient party faces.

[TheHalfAasimar]

Samurai Fighter + Rogue is still a very solid build. Not the most common choice for Rogue/Fighter multiclass, but still very solid.

I wouldn't dismiss CHA as useless for that build, either. Samurai/Rogue can be efficient party faces.

Okay, good point!

*frantically trying to find build*

Okay then, here we go:

7 levels of Samurai to add WIS to Persuasion checks
11 levels of Rogue for Reliable Talent and Expertise in Persuasion, focus on CHA and WIS to make it work.

Only problem? Kinda MAD. Needs Con, another physical stat, CHA and WIS to actually take advantage of a lot of the things.

[Mastikator]

If your goal is just to maximize the damage of a samurai then be a variant human with sharpshooter. Pick up a longbow. The the archery fighting style. Up your dex at 4 and 6.

Fighting spirit + action surge + sharpshooter at level 6 would net you 4 attacks, +5 to hit (advantage), 600 feet range, 1d8+15.
Always combine fighting spirit with action surge.
Don't multiclass either, beeline for that 3rd attack at fighter 11. The ASI at 8 could be used for whatever you think is fun, same for level 12, if you do end up multiclassing then rogue scout is a fine option.

[TheHalfAasimar]

If your goal is just to maximize the damage of a samurai then be a variant human with sharpshooter. Pick up a longbow. The the archery fighting style. Up your dex at 4 and 6.

Fighting spirit + action surge + sharpshooter at level 6 would net you 4 attacks, +5 to hit (advantage), 600 feet range, 1d8+15.
Always combine fighting spirit with action surge.
Don't multiclass either, beeline for that 3rd attack at fighter 11. The ASI at 8 could be used for whatever you think is fun, same for level 12, if you do end up multiclassing then rogue scout is a fine option.

Thanks! Will keep this in mind.

[J-H]

Fighters also don't get their 4th attack at level 17.

[JLandan]

In a rogue/fighter build, I would go Rogue for 1st level. You lose out on some HP (only 2 HP to be precise), but the extra proficiencies more than make up for it. Fighter as a subsequent multiclass loses out on heavy armor proficiency, but if you're mixing with Rogue, you shouldn't need it.

[RogueJK]

Okay, good point!

*frantically trying to find build*

Okay then, here we go:

7 levels of Samurai to add WIS to Persuasion checks
11 levels of Rogue for Reliable Talent and Expertise in Persuasion, focus on CHA and WIS to make it work.

Only problem? Kinda MAD. Needs Con, another physical stat, CHA and WIS to actually take advantage of a lot of the things.

If you're wanting to go this route, and only using XGtE and PHB, I'd strongly recommend Battle Master Fighter instead of Samurai. Due to the MAD of that build, the you're likely only going to be able to have a +1 or +2 WISMOD to add to Persuasion, which isn't all that impactful. And the Samurai Fighting Spirit's major drawback is that it can only be used twice per day. Whereas a Battle Master has a number of maneuvers that can generate Advantage (like Feinting Attack and Trip Attack) and then can use them 4x-5x per short rest (so up to 8x-15x per day, on average).

Something like this:

Half Elf
Battle Master Fighter 7/Swashbuckler Rogue 13
STR 8
DEX 15+1
CON 13+1
INT 10
WIS 12
CHA 14+2
ASIs: 18 DEX, 20 DEX, 18 CHA, Inspiring Leader, 20 CHA, Lucky

Take Expertise in Deception and Persuasion at Rogue 1, followed by Intimidation and Insight at Rogue 6, and you'll be a very effective Face. Swashbuckler not only has class features that key off CHA, it also adds an additional scenario where you can still trigger Sneak Attack even without Advantage or an adjacent ally. (Though having Advantage still means your attack is more likely to hit, and twice as likely to critically hit, so it's the preferable option.)

For Battle Master Maneuvers, take Feinting, Trip, and Riposte at Fighter 3. This gives you two ways to gain Advantage on attacks by either knocking an enemy Prone on your first attack or using your Bonus Action to feint, as well as a way to trigger off-turn Sneak Attacks with Riposte to potentially double your Sneak Attack output in a round. (You can Sneak Attack once per turn, so that means you can SA on your own turn and then again on someone else's turn in the same round, if you have a way to make an off-turn attack like Riposte).

[Unoriginal]

If you're wanting to go this route, and only using XGtE and PHB, I'd strongly recommend Battle Master Fighter instead of Samurai. Due to the MAD of that build, the you're likely only going to be able to have a +1 or +2 WISMOD to add to Persuasion, which isn't all that impactful. And the Samurai Fighting Spirit's major drawback is that it can only be used twice per day. Whereas a Battle Master has a number of maneuvers that can generate Advantage (like Feinting Attack and Trip Attack) and then can use them 4x-5x per short rest (so up to 8x-15x per day, on average).

Something like this:

Half Elf
Battle Master Fighter 7/Swashbuckler Rogue 13
STR 8
DEX 15+1
CON 13+1
INT 10
WIS 12
CHA 14+2
ASIs: 18 DEX, 20 DEX, 18 CHA, Inspiring Leader, 20 CHA, Lucky

Take Expertise in Deception and Persuasion at Rogue 1, followed by Intimidation and Insight at Rogue 6, and you'll be a very effective Face. Swashbuckler not only has class features that key off CHA, it also adds an additional scenario where you can still trigger Sneak Attack even without Advantage or an adjacent ally. (Though having Advantage still means your attack is more likely to hit, and twice as likely to critically hit, so it's the preferable option.)

For Battle Master Maneuvers, take Feinting, Trip, and Riposte at Fighter 3. This gives you two ways to gain Advantage on attacks by either knocking an enemy Prone on your first attack or using your Bonus Action to feint, as well as a way to trigger off-turn Sneak Attacks with Riposte to potentially double your Sneak Attack output in a round. (You can Sneak Attack once per turn, so that means you can SA on your own turn and then again on someone else's turn in the same round, if you have a way to make an off-turn attack like Riposte).

If you add the Tasha's to the book selection, there is at least one Maneuver that help with the CHA skills.

[RogueJK]

There are a number of other build options, but the OP has stated in their various threads that XGtE is the only non-PHB book they have access to.

[KorvinStarmast]

Fighters also don't get their 4th attack at level 17.

Even though they should. I have decided as a DM that Fighters do get their 4th attack at 17 (just as the casters get their cantrip boost there) and I have on file (if we ever get to level 20) to offer an epic boon at 20 (from the DMG) to Fighters at 20 as their capstone.

[TheHalfAasimar]

There are a number of other build options, but the OP has stated in their various threads that XGtE is the only non-PHB book they have access to.

Don't mean to be nitpicky, but I also have Fizban's Treasury of Dragons, but still kinda useless in a rogue/fighter build.

Even though they should. I have decided as a DM that Fighters do get their 4th attack at 17 (just as the casters get their cantrip boost there) and I have on file (if we ever get to level 20) to offer an epic boon at 20 (from the DMG) to Fighters at 20 as their capstone.

Yeah, I like that rule. It just feels more correct than getting extra attack #3 at 20.