D&D 5E The Lady of Pain - 18 Bladesinger/ 2 Fighter build

[Renduaz]

Build

What our character should be.

Race

High Elf - The "Trance" racial trait which reduces our Long Rest from 8 to 4 hours will come very much in handy, while the High Elf's +1 Int and Cantrip ( For which you should choose Booming Blade ) will best augment our character.

Class

Obviously, we are going to pick the Bladesinger here, and at some point dip 2 levels into Fighter, for the Action Surge between every Short/Long Rest and choosing Dueling as our Fighting Style.

Feats

None, for bringing both INT and DEX to 20. In our Marilith form, we can stow a weapon as a free action to cast spells with somatic components should we want to.

Routines

Alright, now to what our combat tactics should be, with the assumption you have access to the spells named, and using our standard build. First of all, I'll make a list of potential "Circumstantial Concentration ( "CON" ) Spells" which should be picked from during the level-dependent routines, since we can only have, convniently, two. Yes, that is two with a Simulacrum, or one at lower levels:

Haste, Enlarge/Reduce, Shapechange

Now let's proceed with that in mind, and you may consult the spell descriptions ( Casting time, duration ) for each to understand why each may be chosen.:

Lowest-level Routine

Preparation - Mage Armor for an AC of 16, and 19 while Bladesong is active, and False Life for an average of 6 temporary HP, with Longstrider for +10 feet of movement, which is 40 and then 50 while Bladesong is active.

In Combat - First of all, when it comes to melee, it is advisable that you wield a Rapier ( Finesse ) which will provide you with the best damage output. Starting from the very first level, with "Booming Blade", your damage per turn is (1d8+5)+(1d8) thunder damage if the target moves on it's turn, which is twice higher than "Magic Missile", and does not consume any of your spell slots. Meanwhile, the expended Mage Armor, False Life and Longstrider will last together for an hour ( Mage Armor for 8 ), while Bladesong is active for 10 rounds, and then another 10 rounds at a time of your choosing. Also, Action Surge will of course double your damage when most needed.

Low-Level Routine

Preparation - All of the above applies, but if willing to spare slots for a melee focus, add pre-castings of See Invisibility and Mirror Image, with "Enlarge" as your concentration.

In Combat - Lowest-level Routine applies, but you now add 1d4 to your strike from Enlarge.

Medium-Level routine

Preparation - Blink ( Just before or at the start of combat ), Fire Shield and a Contingency for Otiluke's Resilient Sphere or Dimension Door in the event of danger should be included.

In-Combat - Much has changed now. "Haste" takes the place of your concentration, you should by now have access to the "Extra Attack" and "Song of Defense" ( Not very relevant though ) class features as well. Our AC should now be higher by 2 from higher DEX ASI and INT ASI for 21 while Bladesong is active, 23 while Hasted, our speed while Hasted is 100 feet, and Booming Blade's damage has likewise probably increased a lot ( 2d8 on strike + 3d8 on moving ), so let's recaculate. We should probably ditch our Extra Attack for the possibility of the enemy moving, for two attacks ( Booming Blade Attack, Haste Attack ), That's going to be ( 2d8+6 ) base + (2d8 ) on the first attack from Booming Blade + ( 3d8 ) if the target moves on it's turn and a potential + ( 2d8 ) fire/cold damage from Fire Shield if it hits us with a melee attack. And we reserve the majority of our spell slots ( Especially if you give up Contingency and Fire Shield ), pretty good.

High-Level Routine

Preparation - By now you should have access to Simulacrum, your new best friend, and probably enough gold to create it. Do so as soon as possible. Once done, there are two ways to use it. Either have it for example Enlarge you ( Or any other concentration spell you wish ), then make it cast Rope Trick and safetly tuck itself away while you're fighting with your own Haste, or alternatively if you're not afraid for it's safety, have it fight alongside you on your turn, using the exact same spells and tactics. Bypassing the Simulacrum's main weakness ( Not being able to regain spell slots, since you're mostly doing melee attacks ), the Simulacrum Bladesinger is potentially as good for as long as you can keep it from melting.

In Combat - With the "Song of Victory" now available, adding our intelligence modifier to every single strike ( And we get 2-3 of those ), our damage increases significantly.

Highest-Level Routine

Preparation - Your Simulacrum may now grant you Foresight, and you'll probably want to Wish fo them in between Long Rests from now on. ( Party takes 8 hours Long Rest, you take 4 hours, Wish for a Simulacrum, and complete another 4 hours Rest for Shapechange next up ). Furthermore, with Spell Mastered Shield and max INT and DEX and Haste, our AC is now 30 with Bladesong, and with Spell Mastered "Rope Trick", your Simulacrum can get into safety while concentrating an Enlarge/something else on you ( No, it doesn't require line of sight or has a distance limitation unless stated otherwise in the spell itself ).

In Combat - We will now make the final damage calculation for our own form in the 20th level, before moving on to the apex of our power. With all benefits, ASI's and so forth present, our combined damage is (2d8+12 ) + ( 3d8 ) + ( 4d8 ) + ( 2d8 ) when not Enlarged. Or in other words, offensive strikes of 2d8 for 2 Rapier Attacks, +5 from Dex, +5 from Song of Victory, +2 from Duelist, 3d8 for Booming Blade, with an average of 64 damage, and an additional potential average of 27. 4d8 more if Enlarged, and doubled if the Simulacrum fights alongside you, all with almost no spell slot expenditure. Alternatively without Booming Blade if you think the enemy won't move, it's ( 3d8+12 ) base damage, slightly higher. But as for the Crown Jewel, it is the Shapechange spell, and choosing to transform ourselves into a Marilith specifically. Keep in mind that we retain all of our statistics except STR, DEX and CON and gain most of the creature's beneficial attributes. While Shapechanged into the Marilith, our AC with Spell Mastered Shield is 32 ( Or 37 if using your Parry ), our CON save is +15 ( Stats, Bladesong ), we have the "Reactive" trait which lets us take a reaction every single turn in combat ( Of any creature including us ), and we make 7 attacks with the Mariliths Longswords and Tail, for which we add our own proficiency modifier of +6, for +10 To Hit. When Hasted with Longstrider, our speed is 120 feet. Our DPR reaches an astoundingly high ( 12d8+9 ) + ( 2d10+9 ) or an average of 128 from our Multiattack alone ( For which we cannot use Booming Blade ). We make one more attack with Haste for ( 2d8 + 9 ) which as a Longsword attack, bringing our Average DPR to 149. Doubled with Action Surge. Tripled, with the Simulacrum ( Whose halved hit points become irrelevant as it gains the Marilith's full health from Shapechange ), or else 18 more average damage if Enlarged from the Simulacrum. With each Longsword blade coated with poison which delivers it's damage per weapon attack ( Purple Worm poison especially ), the damage gets even more absurd. Fire Shield gives you another potential 2d8 damage if the target makes a melee attack against you. With the "Reactive" trait, you can Counterspell every enemy on their turn, or alternatively use "Absorb Elements" to gain up to 8d6 additional elemental damage as a bonus against your next target, on top of everything else.

And that's all, folks.

 

[Rofel Wodring]

Few things amuse me more than magical item-less, medium-to-high level Bladesingers that focus on melee combat to the point of multiclassing, especially when their tricks depend on high-level spells. Yes, that small increase to DPR was totally worth delaying your spell access and not getting an extra 6th and 7th level spell slot.

I always feel that these people would be much more satisfied with Sorceradin builds except at character levels 17+, and that's only if Stone Sorcerer or Old-Favored Soul aren't in play.

 

[Renduaz]

I wouldn't really call our average base DPR of 164 with Shapechange for an hour, and potentially much more than that with reactions not to mention a Simulacrum, a "small DPR increase", nor the consistent 90DPR of the Hasted, Booming Blade, Dual Wielding form, nor do I find the spell access delay or extra 6th and 7th level slots which get burned in 2 turns to be particularly bothersome. As for "Magical item-less", what are you even talking about? A character is probably going to have quite a few by then, this just demonstrates what can be done even without magical items.

Nor do I find my Two Weapon Fighting and Short Rest recharged Action Surge from the beginning to be unappealing.

More satisfied with a Sorceradin at mid-high levels? Is this some kind of joke? For what, 2d8 damage on a strike for maybe about a dozen turns at best ( I don't even know what your build is )? Giving up all of my, still completely available should I want them, Wizard-only/Non-Sorcerer spells? Including Shapechange and Simulacrum? Giving up Spell Mastery? I need to be enlightened because from my perspective I see something objectively worse in every single aspect. Do elaborate. And UA is indeed out of play.

 

[Blue]

First, there's a problem in your combat routine. Booming Blade is a spell that you need to use the Cast a Spell action, not an attack that you take as part of an Attack action. This has several effects:

It's not compatible with extra attack. That comes from the Attack action.
It can't be used during your Haste attack. That is an Attack action (one attack only) or some others, not Cast a Spell.
You need an Attack action (though the one from Haste is okay) to trigger two weapon fighting bonus action, so until you have Haste, if you are using BB you aren't getting your offhand attack.

Second, if you drop the Duel Wielder feat and just take +2 DEX, you can use shortsowrds. The differences are:

Base damage goes from d8+3 to d6+4. Same average, though a point lower on a crit.
+1 to hit
+1 AC
+1 initiative
+1 Dex saves
+1 Dex skills

That +1 to hit will boost your expected damage per attack, especially once Song of Victory is in play.

Third, while Song of victory is quite nice with more attacks, an alternative would be to go Dueling style, single Rapier, and drop warcaster as well since you have a hand free. (You still need that hand for somatic components even with warcaster.) This allows a +5 DEX total. A single attack goes from d8+3 (dex)+5 (SoV) with an average of 12.5 before to-hit, to d8+5 (dex) +2 (style) + 5 (Sov) for an average of 16.5 before to hit. One less attack but about the same total damage, and more likely to land it because of the better to-hit with +5 DEX. And all the other dex benefits like AC and Init.

 

[Renduaz]

That's true I suppose, guess we'll drop Booming Blade in favor of the Extra Attack. We won't be using Booming Blade at the highest level anyway. And we can't use shortswords, because without "Dual Wielder", you can only make an attack as a bonus action with Two-Weapon Fighting if you're using Light weapons. And a single Shortsword attack is significantly less than our Rapier Dual Wielding.

You don't need a hand for somatic components with War Caster... "You can perform the somatic components of spells even when you have weapons or a shield in one or both hands.", although War Caster in my build is really only here if you want to Counterspell and the like as a Marilith. Actually come to think of it, it's not needed at all, since I forgot stowing your weapons ( And you can even stow 2 with Dual Wielder, for Somatic and Arcane Focus ) is a free interaction. I'll have to pick Sentinel instead or something else. Or in act none for dexterity maximum.

With Dueling instead of TWF and Dual Wielder, we actually get the same average judging by Anydice ( 26 and 26 ), but you are right that it does the same damage with the DEX and fighting style bonus, however sadly won't work with Marilith, albeit more gain than loss, so thanks for the advice. Although at highest level, even without Extra Attack, the 3d8+8 of dual Wielder and 3d8 Booming Blade does slightly more damage than 2d8+12 ( Attack, Hasted Attack ) with 3d8 Booming Blade, or 3d8+12 without Booming Blade. Although it's a small reduction, so I'll take it.

 

[Rofel Wodring]

I wouldn't really call our average base DPR of 164 with Shapechange for an hour, and potentially much more than that with reactions not to mention a Simulacrum, a "small DPR increase",

Here's the thing, though. All of those DPR increases don't come from the Fighter levels. They come from the Bladesinger levels. Why are you A) delaying access to these bad-ass show-stopper tricks or B) (discussed below) diluting your effectiveness as a bladesinger at the endgame.

Also, you are way undercounting the value of an extra 6th and 7th level slot. Even if you're not interested in an extra Mass Suggestion or Reverse Gravity and only care about your melee badassery, that's still an extra Bigby's Hand upcasted to 7th level, letting you do 8d8 as a bonus action. Or a more badass Animate Objects, doing up to 14d4+56 damage in a round. Or an extra Contingency, allowing you to fast-cast Haste or Greater Invis or Melf's Minute Meteors if you so choose. Two extra Contingencies is enough to make you a melee god for every major fight of the day. Imagine being able to throw down with a Foresight + Haste (especially with Spell Mastery, so it doesn't even take spell slots between short rests) pretty much every combat of the day, without using up actions. Why the heck would I want to dilute that with some Fighting Style spoon or even Action Surge?

As for "Magical item-less", what are you even talking about? A character is probably going to have quite a few by then, this just demonstrates what can be done even without magical items.

The thing is, while Magical Items definitely increase the viability of Bladesingers focusing on melee, they also push Bladesingers more towards pure spellcasting. Getting a Sunblade or a Flametongue or a Defender or a Holy Avenger does kick major butt, but you're just as likely to be getting things like Staves of Power and Wands of Fireball and Wand of Viscid Globs and Robes of the Archmagi and Ring of Djinni Summoning. If you get a Tome of Clear Thought and a Staff of the Magi (and I've seen both drop in Adventurer's League) are you really going to use your rounds running up and stabbing the enemy with a sword?

 

[Rofel Wodring]

More satisfied with a Sorceradin at mid-high levels? Is this some kind of joke?

No. If what you care about is melee efficacy, Sorceradins completely outclass Bladesingers until around level 13 or so. And if Simacrulum isn't in play (this is the spell most likely to be banned at non-AL tables IMX), until level 17. Quicken Spell is just sickeningly good for them. Quicken Spell + Hold Person + Two Smite Great Weapon Mastery Attacks will completely put to shame anything a Bladesinger can do until Simacrulum comes along.

Of course, since you recommend diluting your build with two levels of Fighter, I'm wondering at what point even your Bladesinger is supposed to shine.

Sorceradins aren't for everyone, especially in tables that don't drop a lot of magical items and/or have long workdays, since their best tricks require a steady source of magical slots for smite and sorcery point fuel. But if you ARE able to finagle a few rings of spell-storing or pearls of power along with other melee-boosting tricks, they stomp a Bladesinger into the dirt in terms of gishy goodness.

Not to diss Bladesingers. They're a great class and probably noticeably overpowered as 'Masters of All'. But they have the same problems as Valor Bards and non-Hexblade Warlocks: pushing them towards melee effectiveness requires hurting their spellcasting capabilities, and spellcasting will just straight-up be more effective than running into melee and hitting people.

 

[Renduaz]

Here's the thing, though. All of those DPR increases don't come from the Fighter levels. They come from the Bladesinger levels. Why are you A) delaying access to these bad-ass show-stopper tricks or B) (discussed below) diluting your effectiveness as a bladesinger at the endgame.

Also, you are way undercounting the value of an extra 6th and 7th level slot. Even if you're not interested in an extra Mass Suggestion or Reverse Gravity and only care about your melee badassery, that's still an extra Bigby's Hand upcasted to 7th level, letting you do 8d8 as a bonus action. Or a more badass Animate Objects, doing up to 14d4+56 damage in a round. Or an extra Contingency, allowing you to fast-cast Haste or Greater Invis or Melf's Minute Meteors if you so choose. Two extra Contingencies is enough to make you a melee god for every major fight of the day. Imagine being able to throw down with a Foresight + Haste (especially with Spell Mastery, so it doesn't even take spell slots between short rests) pretty much every combat of the day, without using up actions. Why the heck would I want to dilute that with some Fighting Style spoon or even Action Surge?

The thing is, while Magical Items definitely increase the viability of Bladesingers focusing on melee, they also push Bladesingers more towards pure spellcasting. Getting a Sunblade or a Flametongue or a Defender or a Holy Avenger does kick major butt, but you're just as likely to be getting things like Staves of Power and Wands of Fireball and Wand of Viscid Globs and Robes of the Archmagi and Ring of Djinni Summoning. If you get a Tome of Clear Thought and a Staff of the Magi (and I've seen both drop in Adventurer's League) are you really going to use your rounds running up and stabbing the enemy with a sword?

Initially delayed for Two-Weapon Fighting, and now at Blue's suggestion altered to Duelist. Action Surge isn't too bad either, especially when you need to land a blow with the kind of damage being packed here. Extra spell slots are always better than less, the question is, whether they'll be better than the 2 levels in Fighter? Especially as a Bladesinger. I've personally reached the conclusion that the +2 from Duelist for example ( Or bonus attack from TWF ), which provide permanent and consistent benefit that adds up quite a bit on every strike, especially in Marilith form, and finally the Action Surge are more useful to me than the extra Mass Suggestion, Reverse Gravity or Bigby. Both of the latter being concentration, and "Shapechange" ( Which puts out the most value for me as a 9th level spell, in HP, damage, versatility, everything. ) being my main concentration spell. Sure I can take Bigby after the whole hour it takes it to run out if I'm in another fight ( And a Long Rest for me is only 4 hours ), but I don't know if the two extra will make the difference.

Melee badassery is not the only thing I care about, it's in fact just the highest DPR I could find, but neither is DPR the only thing I care about. The good thing about this melee badassery though is that I pretty much one/two-shot things for an hour, do consistent damage which wouldn't shame any marital class, and have most of my spell slots intact for any utility or control I need. Or I can switch to melee after exhausting my spell slots. Animate Objects and the rest are all great and I've thought about them, but as you continue on to say, I think that what I got at 18th level already carries me throughout the day. Wheres for an entire dungeon or "boss floor" or massive battle crawl, Shapechange already takes my concentration and will go on for an hour, and with "Action Surge", alongside my Shapechanged, Action Surge capable Simulacrum even, I can basically take down almost any legendary creature all by myself before it can even act and use any of it's dangerous capabilities.

By the way Haste is 3rd level so no Spell Mastery. But at any rate by my reckoning, I already have enough slots that, in the unlikely event that Shapechange didn't finish most of the job somewhere, I can conveniently throw them up as my concentration and conveniently wait until recharging, that "Duelist" and "Action Surge" seem appealing.

As for the Staff, keep in mind the thing about spells like the Fireball or Plane Shift ( Which most appeals to me ), they're either only good for a turn or against a single monster. That being said, it's hallmark 7th level Fireball ( 12d6 ) actually has an average DPR of 42, halved on a successful save ( Which at level 20 would be like what, 80% of monsters? ), and then probably halved yet again with all of the various resistances out there. Although granted, hits several foes if they're clustered. But yes, I would actually find myself fairly often swinging my Rapier with a 50 DPR consistent, no resistance, no halved damage insead.

No. If what you care about is melee efficacy, Sorceradins completely outclass Bladesingers until around level 13 or so. And if Simacrulum isn't in play (this is the spell most likely to be banned at non-AL tables IMX), until level 17. Quicken Spell is just sickeningly good for them. Quicken Spell + Hold Person + Two Smite Great Weapon Mastery Attacks will completely put to shame anything a Bladesinger can do until Simacrulum comes along.

Of course, since you recommend diluting your build with two levels of Fighter, I'm wondering at what point even your Bladesinger is supposed to shine.

Sorceradins aren't for everyone, especially in tables that don't drop a lot of magical items and/or have long workdays, since their best tricks require a steady source of magical slots for smite and sorcery point fuel. But if you ARE able to finagle a few rings of spell-storing or pearls of power along with other melee-boosting tricks, they stomp a Bladesinger into the dirt in terms of gishy goodness.

Not to diss Bladesingers. They're a great class and probably noticeably overpowered as 'Masters of All'. But they have the same problems as Valor Bards and non-Hexblade Warlocks: pushing them towards melee effectiveness requires hurting their spellcasting capabilities, and spellcasting will just straight-up be more effective than running into melee and hitting people.

Hold Person will only work on humanoids, and until you get Spell Mastery, will last you for like a few turns, along with your Divine Smites ( Which will forever stay that way too if you're a level 2/3 Paladin ), and then you're tapped out. And Sorcery Points. That build will probably be utterly drained in a single combat encounter with like 6 goblins. Meanwhile the Bladesinger's main resources to mid-high levels are Bladesong ( 20 rounds ) and Haste ( 1 minute each casting ). And in fact Bladesong won't even give us DPR boost, it's just for the AC and possibly CON I guess. At high levels, it's Shapechange which does the trick, while Simulacru is more "optional", and that Sorceradin still gets tapped out much faster than the 1 hour Shapechange, 20 rounds Bladesong and Haste.

Retracting Fighter will reduce our, by level 6 ( With Extra Attack ) DPR by 6. I guess that could be a lot at these levels, with Marilith it would be down by 16. I suppose that's not really important so the question left is Action Surge vs extra 6th and 7th level slot. Personally I'd pick Action Surge ( Along with my nice damage bonus ) for the ability to land either massive damage or 2 spells in a row right at the start when it's most needed, while trusting that my single 6th and 7th level slots will be enough until I can recharge. It should also be noted that my Action Surge recharges on a Short Rest, while spell slots above 6th level can't be recharged with a Short Rest. So overall I believe that my halved slots should be enough to last me for the encounters, or else that the additional ones won't make a significant difference in the majority of sessions.

 

[Rofel Wodring]

Extra spell slots are always better than less, the question is, whether they'll be better than the 2 levels in Fighter?

Yes, they are. First of all, a big problem with your 'but what about the Shapechange and the Simulacrum!' argument: that stuff comes online at level 17, minimum, which is really level 19 for you. What about all of the other levels in between? Builds that take until 90% of the game is over are looked down upon for a reason, even if you're lucky enough to start there.

As far as pooh-poohing Contingency, you're really underestimating the goodness of that spell, especially at levels 11-14 when its ability to be cast in downtime makes your melee efficacy explode if you want. Even though I mercilessly criticize D&D for having much shorter workdays than the game expects, it's not an hour-long short. What are you doing those other 3 to 11 hours? What are you doing with that concentration slot in the meantime? I guess you're going to go back to using Haste or Greater Invis, but Contingency lets you fast-cast those spells. And even if you're not interesting in fast-casting another concentration spell, you still have a bunch of other fun options to play with: Blink, Mirror Image, Melf's Minute Meteors, Fire Shield, Dimension Door, Dispel Magic, and whatever comes out with Xanathar's Guide to Everything.

And a Long Rest for me is only 4 hours

Long rest, or at least being able to replenish your spells from it, is always 8 hours. That got clarified.

Melee badassery is not the only thing I care about, it's in fact just the highest DPR I could find, but neither is DPR the only thing I care about.

You sure don't sound like you care about stuff because melee efficacy. Any Bladesinger who uses Simulacrum to boost their single-target DPR by 40-60 instead of doing something awesome like, I don't know, Banishing/Wall of Forcing three monsters while you spend the minute casting Symbol or forcing the monster to burn two Legendary Saves in the first round of combat with a double-Otto action has their priorities in the wrong order. Unless you're in a party that lacks martial muscle, DPR in any challenging fights should be a secondary concern for you. You should be worrying about establishing control, because that's what your spells are good at. I know it sucks as a gish to get dice envy when a Battlemaster / Paladin gets TWO crits on an eight-attack sequence, but you're just going to have to deal with it.

Animate Objects and the rest are all great and I've thought about them, but as you continue on to say, I think that what I got at 18th level already carries me throughout the day.

Again, what about the other seventeen levels?

As for the Staff, keep in mind the thing about spells like the Fireball or Plane Shift ( Which most appeals to me ), they're either only good for a turn or against a single monster.

Well, guess what. 5E D&D doesn't really do the 'single monster' trope for most challenging fights. Not that they don't exist, but 90% of the time if published content is anything to go by a hard fight will be something like 'you're level 10 and you're facing 10 ogres, 2 stone giants, 1 cloud giant, 2 hill giants, and 2 fire giants.' 10d8 Chain Lightning to four targets or 10d6 to 12 targets might make you feel small in the pants compared to a Flametongue Double-Attack + Haste + Melf's Minute Meteors, but those will win you the fight faster than pushing all of that onto one monster.

Hold Person will only work on humanoids, and until you get Spell Mastery, will last you for like a few turns, along with your Divine Smites ( Which will forever stay that way too if you're a level 2/3 Paladin ), and then you're tapped out. And Sorcery Points. That build will probably be utterly drained in a single combat encounter with like 6 goblins.

Yes, if you feel dice envy and feel like throwing down at full-force against six goblins, you're going to run out of resources in a typical work day as a Sorceradin. So what? What makes the Sorceradin good is that they have good (rather than average) round-to-round damage with minimal investment (which is not zero!) and they can throw down when it's time to throw down. Unless magical items are in play, it requires some careful, but not strict, budgeting but the results are amazing when you do it right. A Paladin 2 / Old Favored Soul Sorcerer 9 with GMW and a +2 Greatsword can for the cost of a Haste Spell, 2 Sorcery Points for Quicken, and 1 1st-level spell slots for smite can, if all of their attacks hit, do 8d6 (base) + 2d8 (smite) + 2d8 (Booming Blade) + 40 (GMW) + 8 (enhancement) + 16 (strength) = 94 damage for that round. Even more if we have Two-Handed Weapon fighting in play from the paladin. They definitely have simulacrum envy on Bladesinger wizards, but not because their damage can't keep up.

Personally I'd pick Action Surge ( Along with my nice damage bonus ) for the ability to land either massive damage or 2 spells in a row right at the start when it's most needed, while trusting that my single 6th and 7th level slots will be enough until I can recharge.

Action Surge isn't really all that great for Bladesingers, unless, again, magical items are in play. Mostly because the really great spells you'd want to cast in combat are concentration-based. It's best used to fast-cast buffs (which you have Contingency for), fast-cast concentration spells that require double actions like Sunbeam and Eyebite and Telekinesis, or to layer on a little extra pain. Unfortunately, concentration-less spells either tend to be higher level (Mass Suggestion, upcasted Bestow Curse) or instantaneous damage spells like fireball and lightning bolt. Looking at it that way, I'd consider it a fair tradeoff, though skewed slightly in favor of the extra spell slots unless you're using it in a way that wouldn't matter to your build. Using it to get in some more melee damage is, uh, kind of a waste of the ability. If I had shapechange up, I'd rather use it on, say, an extra ancient brass dragon's breath or a double-or-nothing on a Balor's summoning of 1d2 mariliths, personally.

 

[Zene]

<snip>

Awesome topic, very interesting build. I really appreciate the notes on playstyle at different levels. Also appreciate the dialogue on the pros and cons with the other commenters. I just started leveling a bladesinger, and this gives me a lot to think about.

A couple things I noticed -- you mention taking a 4-hour trance long rest, then casting, then taking another 4-hour trance long rest. My understanding is that you can only take one long rest per 24 hours... but am I missing something? Also, in your highest-level routine, you mention shapechange, haste, and enlarge. That's 3 concentration spells, but with you and the simulacrum, there should only be 2. Again, unless I'm missing something.

I'm curious what you'd think about some slight modifications I'm considering to your base build:
1) Headband of Intellect instead of Int ASI's. So you're maxing out a +4 int instead of +5 (and totally missing out on the opportunity for +6 if a tome drops). You'd have -1 AC, -1 Concentration saves, -1 damage per melee hit at high levels, and -1 spell save DC/spell hit bonus. And you'd be giving up an attunement slot. In exchange, you'd free up 2 ASIs for feats, and a few attribute points you could put elsewhere.
2) Getting reincarnated as a human for the extra feat.
3) Instead of 2 levels in fighter for action surge, taking 1 level in rogue for expertise in Athletics; opening up some crazy shapechanged grappling options as a giant or dragon when you don't want to just DPR.

What do you think? Are any of these worth it to open up other options, if you're not super concerned about max DPR?

Long rest, or at least being able to replenish your spells from it, is always 8 hours. That got clarified.

When and where? Latest Sage Advice column (just a few days old) says the opposite. Are you talking about a more recent clarification than that?