Harmonized Mia

Weapon: Summer Strikers

Assist: Rally Assist / Flexible

Special: Luna / Miracle

Passive A: Fury (3 or 4) / Swift Sparrow 3

Passive B: Lull Spd/Def / Lull Atk/Def / Lull Atk/Spd / Wings of Mercy

Passive C: Panic Smoke / Spd Smoke / Atk Smoke / Pulse Smoke

Sacred Seal: Hardy Bearing / Swift Sparrow / Quickened Pulse

• Summer Striker's damage mitigation on incoming enemy attacks basically gives Mia/Marth an almost-ultimate survivability option when initiating attacks. Additionally, their cavalry movement and ranged status gives them large territorial dominance on most Aether Raid maps. Thus, an Aether Raids Defense-based build is also in the realm of possibilities for them.
• Generally speaking, the game plan: the duo will attack incoming enemies, likely survive and already deal some neat damage thanks to Summer Strikers, get support from Wings of Mercy users or refresher units, and wreak havoc on other Offense enemies if they are in range.
• A lot of skills here are familiar to the previous offensive build, but with some narrowed down, Aether Raids-focused options.
  • On Rally Traps, a Rally skill is essential if Mia/Marth acts as your Rally unit, effectively expanding their attack range when paired with refresher units. It can be replaced with other Assists or no Assist at all otherwise.
  • Luna is a preferred Special as the activation timing (2 CD after Summer Striker's Slaying effect) works out against the majority of enemies taking on Mia/Marth—which are likely bulky Distant Counter units. After the Duo's initial hit and the enemy's counterattack, the Duo will likely follow up with a strong Luna-charged attack in one round. Alternatively, Miracle can be run with Quickened Pulse to add an extra layer of survivability on top of Summer Striker's damage reduction. 
  • While forgoing Mia/Marth's already-fantastic default A slot skill in Swift Sparrow might seem like outright sacrilege, Fury has a few noteworthy benefits. Primarily, it helps Mia reach below 50% HP faster, which paves the way for allies with Wings of Mercy to teleport in and offer their help. Additionally, the extra defensive stats aid somewhat in better survivability while compromising little in Mia/Marth's offense.
  • A Lull skill gives the Duo the best combat performance of any other B slot skill by shutting down the visible bonuses of buff-reliant enemies. A less expensive option would be Wings of Mercy, which gives Mia/Marth the ability to teleport to badly-damaged allies and offer support.
  • Mia/Marth's C slot serves an actual purpose here as it expands their mass debuff potential with Smoke skills.
    • Panic Smoke is generally best against teams reliant on visible bonuses, though Spd Smoke and Atk Smoke are perfectly cheap and viable alternatives which serve to swing stats further along with the Dagger 7 debuff.
    • For setups that are otherwise extremely weak to Duo Alfonse, Pulse Smoke essentially puts him out of commission. More specifically, it knocks him out of precharged Open the Future! after combat or assuming he's near an attacked ally.
  • Hardy Bearing provides essential immunity to Vantage units while making matchups versus Brave Ike more comfortable (especially due to Urvan affecting the Duo's attack pattern). If you have Hardy Bearing elsewhere, it can otherwise be dropped for the standard but awesome-as-always Swift Sparrow seal.

Weapon: Summer Strikers

Assist: Reposition

Special: Moonbow / Glimmer / Luna

Passive A: Swift Sparrow 3

Passive B: Lull Spd/Def / Desperation / Spd/Def Snag / Lull Atk/Spd / Lull Atk/Def

Passive C: Atk/Spd Gap / Flexible

Sacred Seal: Swift Sparrow / Death Blow / Heavy Blade

• Our odd duo fortunately comes with most of the skills necessary for their competitive success. An easy general gameplay, player phase-based build can be built off their base kit right away.
• The build is centered around the unique dagger weapon Summer Strikers, which is a very powerful weapon thanks to its slaying effect, huge incoming damage mitigation, and a free, beefy Atk/Spd boost during combat. As a result, the duo attains relatively safe initiations across the majority of matchups and deals powerful colorless dagger damage meanwhile. However, two of the latter effects require the duo to start combat above 25% and initiate combat themselves. Ultimately, using Summer Strikers limits them to a frontlining-exclusive playstyle. Fortunately, with the given tools, they're fantastic at that!
• Swift Sparrow 3 comes as a fantastic default A slot skill, and basically is never worth replacing for a few reasons.
  • Swift Sparrow specializes Mia/Marth further in player phase—the only phase worth talking about when using Summer Strikers—and doesn't compromise her bulk or HP level unlike other common offensive A slot skills such as Life and Death or Atk/Spd Push. This aspect is important as Summer Strikers's effects stop working when Mia/Marth's health is below 25% HP.
  • As such, it can also be doubly applied by using the Swift Sparrow seal in the Sacred Seal slot for further offensive dominance.
• The other aspects of the build are relatively straightforward save for the choice in B slot skills:
  • For short-lived matchups, Lull Spd/Def is a solid choice as it swings many matchups significantly more favorably in Mia/Marth's favor. Additionally, the massive damage reduction from Summer Strikers in such situations makes Desperation a mostly unnecessary option. Alternatively, Lull Atk/Def or Lull Atk/Spd can be run in conjunction with Luna and Heavy Blade to help proc Luna in a single sitting while swinging Attack comparisons in Mia's favor.
  • If you're confident in your ability to keep Mia/Marth's HP in a sweet spot between 25% and 75%, however, Desperation is their best option for general sweeping and safe initiations.
  • Spd/Def Snag is a good default option which allows Mia/Marth and their allies to selectively debuff an in-range enemy and close in for a better kill. Unlike the other listed options, however, this must be done out of combat.
• The Duo's C slot isn't terribly important in the scheme of general gameplay, and can be suited depending on team needs. Their default Atk/Spd Gap is generally an already solid option for supporting other sweeper role allies, however.

Weapon: Broadleaf Fan+ (+Atk) / Broadleaf Fan (+Spd)

Assist: Reposition

Special: Glimmer / Miracle

Passive A: Close Counter / Close Foil

Passive B: Vantage

Passive C: Atk Smoke / Pulse Smoke / Spd Smoke

Sacred Seal: Heavy Blade / Fierce Stance / Atk Smoke / Spd Smoke

• Mia/Marth can also run an Aether Raids Offense build of a familiar yet overrated flavor: Broadleaf Fan + Vantage. If you aren't already familiar with why this setup manages to worm its way in most dagger units' analysis, here's the cram session:
  • Broadleaf Fan's damage is based on the total amount of debuffs currently applied on the target. Assuming the Dagger 7 effects and equivalent Spd and Atk debuffs are in place (you can apply that by using Smokes of those stats in the C and Sacred Seal slots), Mia/Marth can gain an additional massive and deadly 28 Attack against her opponent.
  • Combined with Mia/Marth's already nice offensive might, preexisting damage (likely from Bolt Tower), and other forms of support (such as Duo Micaiah's Domination effect), this combination can potentially wipe out entire groups of enemies. It's not an instant win, however, as this assumes optimal setup and the right targets eliminated—especially units with Hardy Bearing and counterattack cancellation skills.
• Mia/Marth's key trait of differentiation is the cavalry movement, which enables them to more quickly cover space and efficiently target units and structures. Being a cavalry unit also tends to make them easily qualified for Tactics boosts—the current Offense Mythic heroes at this time of writing are fliers or infantry units themselves.
• If you already have a certain stat debuff covered (Atk or Spd in particular), this makes running certain Smoke skills redundant. Instead, you can opt outfit the C slot of Sacred Seal slot of that stat with:
  • Pulse Smoke to simultaneously cripple precharged Special-reliant setups.
  • Heavy Blade to quicken the rate of Glimmer's activation to every other hit instead of two. 
  • Fierce Stance for better non-Special damage overall.

Weapon: Pumpkin-a-Box+(No refine) / Pumpkin-a-Box+(+Spd)

Assist: Reposition

Special: Glimmer / Moonbow

Passive A: Fury 3 / Fury 4

Passive B: Disarm Trap / Vantage / Desperation / Escape Route

Passive C: Savage Blow / Smoke skills

Sacred Seal: Savage Blow / Smoke skills

• First and foremost, players should NOT run this build and just scroll by if their current build:
  • Cannot reach ≤50% HP after two rounds of combat
  • Lacks Pumpkin-A-Box entirely
• This build is quite extremely different from the others in that it stops revolving around Summer Strikers; it's entirely absent from the build. Rather, it utilizes both Pumpkin-a-Box and Fury in the A slot specifically to achieve a certain objective: to enable Mia/Marth to become a "teleportation beacon" for other allies in their Raiding team with Wings of Mercy. Said allies can seize this opportunity to support Mia/Marth further with dancing, further the chain of attacks with precharged Galeforce builds, or both.
• Like Summer Linde, Gunnthra, and Ursula, Mia/Marth can perform this build with neat results thanks to:
  • Cavalry range
  • Great offenses
  • Access to Disarm Trap (for uninterrupted attacks and trap testing)
  • Most importantly, low HP values
• HP accounting is unambiguously important as these units are expected to achieve Wings of Mercy's effect condition in two successful combats (meaning Mia/Marth has to be danced at least once between). Depending on the FINAL amount of HP your Mia/Marth achieves as well as access to Fury 3 or 4, it is important take their final HP into account before choosing Fury 4 or to refine Pumpkin-a-Box. Additionally, running two Offense Mythic heroes (which is usual to maximize the amount of Lift you gain) puts Mia/Marth at a base HP value of 48 (assuming no HP Flaw).
  • Without any further modifications to HP, unrefined Pumpkin-a-Box and Fury 3 (equating to 12 damage after combat) are enough to put them at 24 HP (50% of 48) after two rounds of combat.
  • Fury 4 + Pumpkin-a-Box (equating to 14 damage after combat) allows the maximum recommended HP cap to increase to 56 as Mia/Marth can lose 28 HP after two rounds of combat. This is recommended if they achieve increased HP for any reason (such as choosing to refine Pumpkin-a-Box, merging Mia/Marth, etc).
• To soften nearby enemies after multiple rounds of combat, a Smoke-type skill should be taken in both the Sacred Seal and C slots, and this really depends on the types of allies you pair Mia/Marth with.
  • Savage Blow lends itself best to allies that aim to kill in single hits on weakened enemies.
  • Spd and Atk Smoke are best for Galeforce units that need stat comparisons in their favor to activate Flashing or Heavy Blade.