Legendary Marth

Weapon: Unbound Blade+ (+SPD) / Slaying Edge+ (+SPD)

Assist: Reposition / Flexible

Special: Noontime / Sol / Fire Emblem

A Passive: Distant Counter

B Passive: Spurn / Null Follow-Up / Close Call / Repel / Quick Riposte 

C Passive: Pulse Smoke / Joint Drive Atk / Joint Drive SPD / Atk Smoke / Def Smoke / Spd Smoke 

Sacred Seal: Spd/Res Solo / Atk/Spd Solo / Mystic Boost / Quick Riposte

• Unbound Blade allows Marth to maximize his tanking capabilities since the weapon not only prevents any form of ATK buffing on the foe but also debuffs the foe for 5 ATK so long as Marth isn’t adjacent to any allies. Likewise, you can refine the weapon for SPD, so he can extend the effectiveness of damage reduction skills. As a result, foes will be doing less damage overall to Marth.
   
• If Unbound Blade is not an option, Marth can take up a Slaying Edge and run Sol for better sustainability. If one were to run Brave Lucina support on top of that, Marth would be able to retaliate with Sol every time. Similarly, he can refine it for SPD so he takes less damage overall. Thus, improving upon his sustain. Of course, if you wish to keep Fire Emblem, running Slaying Edge will remove the need for Brave Lucina support as he will always retaliate with Fire Emblem. Just bear in mind that he will need some form of sustain such as with Mystic Boost as his seal.
   
• Noontime and Sol are fairly standard specials when it comes to sustaining, and more often than not, it’s accompanied by allies who can reduce his cooldown much faster, such as with Brave Lucina. Of course, if you wish to keep Fire Emblem as his special, you can always run Mystic Boost as his seal so that he can at least gain some HP from combat.
   
• Distant Counter is also another imperative skill when it comes to enemy phasing foes. It’s especially important when a good amount of foes you’ll be going up against are ranged threats, so Marth will need to have the ability to counter foes from afar.
   
• Given the nature of his class, Marth is rather flexible in what B Passives he can run. In some cases, it might be better to run Null Follow-Up instead of a damage reduction skill since there are a lot of threats that either has guaranteed follow-up attacks or prevent follow-up attacks with impact skills. If Null Follow-Up is out of the budget, Marth can run Quick Riposte. Quick Riposte turns impact skills into SPD checks and since Marth has naturally good SPD, he can more than easily double through impact skills. Beyond that, one can also run Flayn as a support unit if they are concerned about not having any form of damage reduction, so there are plenty of available options for the player to make use of that isn’t damage reduction B Passive.
   
• Pulse Smoke is nice to have as it can help prevent foes specials from slicing through Marth’s damage reduction skills. Of course, if they don’t have any active specials, you can always run Joint Drive ATK or Joint Drive SPD. Joint Drive ATK bolsters the damage output from Marth and can lead him to gain more health from Noontime/Sol damage. Likewise, Marth can run Joint Drive SPD to further improve upon his damage reduction capabilities and, if running Fire Emblem, improve damage output from his special. If none of these are available options, Atk Smoke, Def Smoke, and Spd Smoke are perfect substitutes since they can replicate the same effects as the Joint Drives, only they take combat to set up.
   
• Finally, there are the sacred seals, and depending on how you wish to run Marth, there are plenty of options to choose from. Two of the go-to options are Spd/Res Solo and Atk/Spd Solo. The solo seals will bolster the overall performance of Marth’s sustain: extra ATK for more Noontime/Sol damage, extra SPD for more damage reduction, and extra RES for taking magical hits better. Likewise, you can run Mystic Boost if you wish to keep Fire Emblem as his special. You can also run Quick Riposte with any damage reduction B Passive so that you can negate Impact skills. All of these seals fit nicely with the appropriate skills in mind.

Weapon: Ninja Katana+ / Slaying Edge+ (+SPD) / Brave Sword+

Assist: Reposition / Flexible

Special: Galeforce / Fire Emblem

A Passive: Swift Sparrow (2 or 3) / Flashing Blade (3 or 4) / Atk/Spd Solo (3 or 4) / Atk/Spd Push 4

B Passive: Lull Spd/Def / Close Call / Hit and Run / Wings of Mercy

C Passive: Time’s Pulse / Pulse Smoke / Spd Smoke / Def Smoke / Joint Drive ATK / Joint Drive SPD

Sacred Seal: Flashing Blade / Quickened Pulse / Atk/Spd Solo / Swift Sparrow

• Ninja Katana is used to not only help proc Flashing Blade checks but allow Marth to charge up his Galeforce before the foe can retaliate and potentially defeat Marth in the process. For budget purposes, you can still run a Brave Sword and be fine as the SPD loss can be made up with passives. However, given how low MT the weapons are, if you are worried about damage output, you can always run a Slaying Edge with a SPD refine as that will not only make Galeforce a 4 CD special but also alleviate the need for Time’s Pulse/Quickened Pulse.
   
• The nature of Marth’s statline and class type means he can fully take advantage of Galeforce if he so wishes. For example, he can run Flashing Blade 3 or 4 as his SPD stat is relatively good at a base of 36. Likewise, because he is an infantry unit, he can run Time’s Pulse which will always make Galeforce into a 4 CD special at the beginning of his Player Phase.
   
• Depending on which slot you want Flashing Blade to occupy, you can either run skills that increase his ATK and SPD in his A Passive or as his Sacred Seal. There are pros to either method. Running Flashing Blade as his A Passive allows Marth to run the tier 4 variant which grants true damage as long as he outspeeds his foe. Likewise, if he runs Flashing Blade as his Sacred Seal, he can run skills in his A Passive that increase his ATK and SPD much more significantly such as with Atk/Spd Push 4 and Swift Sparrow.
   
• It becomes much more interesting when you get to his B Passives as there is a lot more variety with how he can Galeforce. If you want him to secure kills while also securing Flashing Blade checks, you can run Lull Spd/Def as his B Passive. Likewise, you can run a hit-and-run set with either Close Call or Hit and Run. Close Call gives Marth the ability to survive more combats if he misses any kills in the process as damage reduction skills work in both phases. However, Hit and Run can be more than enough in a lot of scenarios and since both move the unit a space back, either option is fine. Finally, there’s Wings of Mercy. Wings of Mercy can be used for Galeforce Chaining, similar to how dancers run Wings of Mercy except rather than refreshing, you attack instead. Likewise, you can ditch Galeforce and run Slaying Edge with Time’s Pulse so you can trigger Fire Emblem twice in a single combat, assuming the foe attacks back, as Time’s Pulse with Slaying Edge will turn Fire Emblem into a 0 CD special.
   
• Time’s Pulse is a recommended C Passive for Galeforce Marth as the brave weapons lack slaying. However, as previously mentioned, if you choose to run a Slaying Edge instead, then you won’t need Time’s Pulse and can substitute that skill for Pulse Smoke, Spd Smoke, or Def Smoke as well as Joint Drives if you plan on using Wings of Mercy.
   
• Finally, there’s the sacred seal, which will completely depend on what weapon, A Passive, and C Passive is being used. If you happen to have a free Sacred Seal slot, you can always run more skills that increase ATK and SPD such as Atk/Spd Solo and Swift Sparrow.

Weapon: Exalted Falchion

Assist: Reposition / Flexible

Special: Fire Emblem

A Passive: Death Blow (3 or 4) / Swift Sparrow (2 or 3) / Flashing Blade (3 or 4) / R Duel Infantry (3 or 4)

B Passive: Binding Shield

C Passive: Time’s Pulse / Rouse Atk/Spd / Atk/Spd Oath

Sacred Seal: Atk/Spd Solo / Spd/Res Solo / Swift Sparrow / Death Blow / Flashing Blade / Quickened Pulse

• Marth comes almost kit-ready as his Exalted Falchion and Binding Shield is more than enough to help conquer dragons in Arena Assault. However, there are still plenty of A Passive and C Passive options that you can consider when running him as an AA check.
   
• If you plan on using him in your first match, R Duel Infantry is definitely not a bad option, especially R Duel Infantry 4, as that will help with overall scoring. Of course, if you plan on using him in any other match, you can run Death Blow, Swift Sparrow, or Flashing Blade. Because Binding Shield gives a guaranteed follow-up, Marth won’t have to rely on Spd to double against dragons as long as the foe doesn’t have Null Follow-Up, in which case you can run Swift Sparrow. Likewise, if you’re looking to trigger Fire Emblem in every combat, you can run Flashing Blade or, optionally, Time’s Pulse as Marth’s C Passive.
   
• Binding Shield is what arguably makes Marth one of the best dragon checks in AA as dragons cannot counter back. That includes both Sothis’ despite having dragon effectiveness immunity.
   
• If you don’t plan on running Flashing Blade, you can always run Time’s Pulse to secure Fire Emblem special procs during combat. However, you can also run skills such as Rouse Atk/Spd and Atk/Spd Oath to compliment his Bonus Doubler PRF and secure more doubles and kills.
   
• If Flashing Blade and Time’s Pulse aren’t available options, you can always run Quickened Pulse, so that the first combat is guaranteed to proc Fire Emblem. Otherwise, you can run skills that increase Marth’s ATK and/or SPD stats such as Atk/Spd Solo and Swift Sparrow.