Barst

Weapon: Devil Axe (+Eff)

Assist: Reposition

Special: Ruptured Sky / Bonfire / Luna / Moonbow / Glimmer / Ignis

Passive A: Fury (3 or 4) / Fierce Breath / Steady Breath / Brazen Atk/Def

Passive B: Wrath 3

Passive C: Time's Pulse / Infantry Pulse / Flexible

Sacred Seal: Brazen Atk/Spd / Quickened Pulse / Brazen Atk/Def / Sturdy Blow

• This build doubles down on the refined effect of Devil's Axe. By having Wrath doubly applied in both Barst's weapon and the B slot, Barst is able to:
  • Passively charge his Special twice as fast as the average Wrath unit, meaning 2-3 CD can be instantly charged depending on the rest of this build's setup.
  • Gain an additional 20 true damage on top of whatever his Special is already doing on activation! This alone allows Barst to overcome many otherwise impossible matchups.
  • However, due to the "wait-and-see" approach of this build, Barst relies on the power of one-shots and typically must wait a turn after every successful match for his Special to charge.
• The Special in question depends on preferences and whether you're able to provide Time's Pulse in the C slot or not.
  • 2 CD Specials like Moonbow, Glimmer, or Ruptured Sky (you can get it from Female Byleth while inheriting Wrath or Fury 4 or both) are fair game on Time's Pulse-less builds as they instantly charge per turn from double Wrath.
  • Builds utilizing Time's Pulse can instantly have Luna and Bonfire ready after every safe turn, as double Wrath plus Time's Pulse equates to an instant 3 cooldown charged.
  • Ignis is a neat option to consider no matter the presence of Time's Pulse. Here are some combinations to consider and why:
    • Time's Pulse + Ignis: does not require Barst to have a Breath-type A-slot skill or Infantry Rush support, as Ignis can proc in one counterattack after double Wrath charging + the CD reduction of Time's Pulse.
    • Steady Breath / Fierce Breath + Ignis: After double Wrath charging and with a Breath skill, Barst can proc Ignis on any enemy counterattack without the CD reduction of Time's Pulse.
• Though running Fury and Devil's Axe together seems like a recipe for disaster due to doubly placing a timer on Barst's survivability, this is actually beneficial as it helps Barst get to Wrath range (and Brazen skill range if used) even quicker after initial combat. Otherwise, Brazen skills (they activate more often than not from Devil Axe's recoil alone) or Breath skills (their benefits are mentioned when discussing Specials).
• Seals that further complement Wrath (Brazens being recommended) or simply help out Barst's offensive stats top the list of Seals.
  • Furthermore, one may consider Quickened Pulse for more instant Special charging, especially in combination with Time's Pulse.

Weapon: Devil Axe (+Eff)

Assist: Reposition

Special: Moonbow / Luna / Bonfire / Glimmer

Passive A: Fury (3 or 4) / Swift Sparrow (2 or 3) / Brazen Atk/Spd (3 or 4) / Life and Death (3 or 4)

Passive B: Desperation / Escape Route / Null Follow-Up / Lull skills

Passive C: Even Spd Wave /  Flexible

Sacred Seal: Brazen Atk/Spd / Swift Sparrow / Flashing Blade / Heavy Blade

• Here it is: the oldest art known to all offensive units, otherwise known as Fury-Desperation. This build is variant of the previous Wrath build, except it focuses further on developing Barst's combat skills without waiting passively for Special-charged one-shots. In particular, it also allows Barst to exercise his excellent resulting stats, especially his Speed (which typically never factors in one-shot Wrath builds).
• Change occurs particularly in his B slot.
  • Desperation is cheap, effective, and ultimately safe as it enables Barst to make any follow-up attacks immediately mostly without putting himself in danger of killing hits. It also combos well with the Wrath effect of Devil Axe due to being able to activate powered up Special in quick succession.
  • Escape Route is easy to activate thanks to Devil Axe and maximizes Barst's movement options after he gets into range. It is a useful option in timed modes such as Aether Raids, Rival Domains, and Grand Conquests.
  • Null Follow-Up and Lull skills (especially Lull Atk/Spd, Spd/Def, and Atk/Def) are more luxurious options that ease matchups with follow-up disruptive skills or stat-rich enemies, respectively.
• The rest of the build has mostly standard offensive options.
  • Honor is given to Swift Sparrow for the A slot and seal as Barst is less reliant on getting into low health.
  • The defense drops suffered from Life and Death are cushioned by the stats provided by Devil Axe (and Barst's Resistance is nothing to write home about anyway).
  • The C slot is flexible as always depending on your ability to provide certain forms of ally support to Barst. Speed-increasing Wave skills in particular are an easy way to increase Barst's offensive potential self-sufficiently.

Weapon: Devil Axe (+Spd) / Devil Axe 

Assist: Reposition

Special: Galeforce

Passive A: Fury (3 or 4)

Passive B: Desperation / Wings of Mercy / Null Follow-Up

Passive C: Time's Pulse / Atk Smoke / Spd Smoke / Savage Blow

Sacred Seal: Flashing Blade / Heavy Blade

• Galeforce is the main point of concentration on this build; it gives Barst an additional action after activation, allowing him a number of follow-up options including escaping enemy range or going for another kill.
• Since Galeforce does not deal combat damage, it follows that the standard Wrath refinery effect of Devil's Axe is nearly useless here.
  • Therefore, a Speed refine is preferred for a direct increase in Speed as well as +5 HP.
  • If you do not want to waste Divine Dew or increase Barst's HP more than necessary (this is important for Wings of Mercy chains in modes like Aether Raids, in which Barst must reach ≤50 as soon as possible), simply using the base Devil Axe alone will suffice as it still provides a potent offensive boost by its lonesome.
• Fury is recommended above other options in the A slot as it enables Barst to become a teleportation beacon for other allies using Wings of Mercy, which is a potent Aether Raids Offense and Defense strategy.
  • Other standard offensive A-slot skills like Swift Sparrow do the job if one cares less about this and more about pure performance. However, this may end up making Barst a rather generic Galeforce pick compared to others.
• In the B slot:
  • Desperation is easily the safest choice as Galeforce enables Barst to engage in multiple subsequent fights, meaning he becomes more susceptible to killing hits after a while. Desperation lowers the chances of losing to a killing hit should Barst be able to make a follow-up attack.
  • Wings of Mercy can be used with the help of other allies that can get into low health on their own, creating a chain of fighters that can teleport and use Galeforce anywhere on the map.
  • Null Follow-Up decreases the risk of having a Galeforce sweep ruined by follow-up manipulation skills, such as Wary Fighter, Great Flame, and armors attempting to one-round KO Barst with Bold Fighter.
• Time's Pulse is generally the best choice in the C slot as it helps Barst charge Galeforce on units that can't counterattack; without it, Barst can fall short of 1 CD from completing the charge. Those that are confident in their chances, however, can otherwise run Smoke-type skills to debilitate nearby enemy groups, especially Aether Raid Defense setups.
• A Blade-type skill as the Sacred Seal is pretty much necessary on this build to help Barst consistently activate Galeforce in one round. Otherwise, Barst is forced to deal with its long disruptive cooldown every time he needs to get into the thick of things. The Seal you choose depends on whether you feel more confident in manipulating or relying on Attack or Speed comparisons.