Analysis by Adonyx
Byleth (M) - Tested Professor


Obtainable as a 5 only

Hero Stats

Max Avg Total Stats at Lvl 40
HP 40
ATK 36
SPD 38
DEF 34
RES 20

Stat Variations

Level 1 Stat Variation
Low 17 11 7 7 2
Middle 18 12 8 8 3
High 19 13 9 9 4

Level 40 Stat Variations
Low 36 33 35 31 17
Middle 40 36 38 34 20
High 43 39 42 37 23

IV Sets

Key stats worth increasing through nature if possible.
Complementary stats that matter, but not to the point of picking them over key stats for nature increase.
Relatively worthless stat that can safely be decreased through nature.


  • +SPD: Byleth has excellent base Speed, and increasing it further will give him strong matchups against even the fastest enemies. He also gains +4 instead of +3 with a +SPD Asset.

  • +ATK: Depending on the game mode, Byleth may sometimes be better off increasing his Attack over Speed (such as in Arena where upper tiers are mostly comprised of armored units). However, +ATK is generally not quite as good as +SPD.

  • +RES: Byleth doesn’t have particularly impressive Resistance and doesn’t gain anything particularly significant from a +RES Asset. However, his access to the Creator Sword makes him an extremely versatile unit in Aether Raids, so increasing his Resistance will help improve his primary weakness.


  • -DEF: Byleth has decent Defense so taking a -DEF Flaw isn’t particularly ideal. However, if utilizing Byleth in Aether Raids, then it’s important to preserve his magical bulk as much as possible to help withstand stronger defense setups.

  • -HP/-RES: Outside of Aether Raids, Byleth can make do with either a -HP or -RES Flaw. -HP isn’t ideal since he takes -4 instead of -3 to the stat, but won’t have a significant impact on his performance.

Skill Sets

Genesis (Aether Raids)

Build by
Creator Sword A Distant Counter
Reposition B Null C-Disrupt 3
Alternate: Wrath 3
Noontime C Pulse Smoke 3
Alternate: Atk Smoke 3
IVsSDarting Stance 3
Alternate: Quick Riposte 3

Show Explanation/Analysis

Preferred IV: +RES or +ATK or +SPD / -HP or -DEF / Neutral

  • Most IV combinations can work with this build, as they pretty much all have notable strengths and weaknesses. Improving Byleth’s Resistance is recommended to help him withstand heavy magical nukes, though he’s unlikely to be able to survive strong blue magic nukes like Ophelia or Reinhardt without significant preparation.

Weapon: Creator Sword

  • Each of Byleth’s Creator Sword’s three abilities are all individually quite powerful. Having access to all three at once makes Byleth extremely versatile since it frees up his skill choices significantly, such as having access to both Null Follow-Up (in the Creator Sword) and Null C-Disrupt (via the B skill). 

Assist: Reposition

Special: Noontime

  • Sustain is vitally important for a superunit strategy in Aether Raids, and combining Noontime with Creator Sword’s accelerated Special trigger effect allows Byleth to activate Noontime on every counterattack. The main issue with this is typically that his damage output may be a bit lacking, but he has more than enough damage output (with the proper team support) to handle the majority of threats.

Passive A: Distant Counter

  • Byleth conveniently has Distant Counter in his base kit, allowing him easy access to the crucial ability to tackle both melee and ranged threats.

Passive B: Null C-Disrupt / Wrath / Lull Spd/Def / Chill Spd

  • Because Byleth has access to essentially Null Follow-Up in his weapon, he can then run Null C-Disrupt and be able to tackle basically every major threat on Aether Raids defense setups. The primary threats to him at this point are those with overwhelming damage potential like Ophelia or Legendary Alm, both of which can be dealt with by other means.

  • Aside from Null C-Disrupt, Byleth can also opt to use Wrath for a bit of increased damage output in a pinch; the +10 damage can often kick in precisely when he needs that extra bit of damage to get as much healing as possible out of Noontime as well as help secure KO’s. 

  • Otherwise, Byleth can run a wide variety of skills in his B slot based on player preference such as Lull Spd/Def or even his base Chill Spd.

Passive C: Pulse Smoke / Atk Smoke 

  • Pulse Smoke is an incredibly potent skill that can completely neutralize many of the biggest threats on Aether Raids defense setups, namely units with pre-charged Specials. These are most prevalent with units like Ophelia and/or Infantry Pulse setups. Neutralizing these Specials will drastically reduce the incoming damage, allowing Byleth to both tank the damage and heal back up with Noontime.

  • Aside from Pulse Smoke, Atk Smoke is a good budget option to help reduce incoming damage. 

Sacred Seal: Darting Stance / Quick Riposte / Distant Def

  • Both Darting Stance and Quick Riposte greatly improve upon Byleth’s ability to double enemies during Enemy Phase, but both have significant pros and cons. Darting Stance can be foiled by units with obscene amounts of Speed (Legendary Alm is particularly difficult to deal with) but assists defensively by helping deny more enemy doubles from raw Speed. Quick Riposte is quite consistent at allowing doubles, but can be negated by enemies with skills like Null Follow-Up and doesn’t prevent Byleth from getting doubled if his opponent has enough raw Speed.

  • Alternatively, Byleth can utilize Distant Def to improve his raw bulk to help ensure survivability.

Pierce the Sky (Offensive Generalist)

Build by
Creator Sword A Distant Counter
Alternate: Fury (3 or 4)
Reposition B Wrath 3
Alternate: Ruptured Sky
C Odd Spd Wave 3
IVsSQuickened Pulse

Show Explanation/Analysis

Preferred IV: +SPD or +ATK / -HP or -RES

  • As this is primarily an offensive set, increasing Byleth’s offensive stats are ideal.

Weapon: Creator Sword

  • Creator Sword’s accelerated Special trigger makes it a fantastic weapon for a rapid-fire nuke setup. Its other abilities massively enhance Byleth’s offensive potential due to overriding multiple setups that would otherwise shut down his damage output (such as Special Fighter, Steady Stance 4, or Swordbreaker).

Assist: Reposition

Special: Moonbow / Ruptured Sky

  • The difference between Moonbow and Ruptured Sky will vary drastically depending on the type of opponents Byleth is fighting, so it’s hard to objectively say which one is better than the other. The choice is mostly up to player preference, though it seems that Moonbow is generally a bit more consistent. 

Passive A: Distant Counter / Fury (3 or 4)

  • Byleth’s base Distant Counter works great with this setup, as although it’s a heavily offensively oriented setup, he still greatly benefits from the versatility offered by the ability to deal with ranged units during Enemy Phase.

  • Alternatively, Fury is a great option to simply improve upon all of Byleth’s stats. The post-combat recoil damage can also be helpful in pushing Byleth into the HP threshold for Wrath.

Passive B: Wrath

  • Wrath is a key component of this build, as it significantly improves upon Byleth’s overall damage output through his constant Special activations. It also gives him a fairly safe option after his first combat to engage other opponents, as otherwise he may have taken too much damage to safely fight otherwise.

Passive C: Odd Spd Wave / Flexible

  • Byleth’s C skill is completely flexible with this build, but his base Odd Spd Wave will work great if he doesn’t have access to buff support from his team.

Sacred Seal: Quickened Pulse

  • The Quickened Pulse Seal is a fantastic choice for this build as it allows Byleth to immediately activate his Special when attacking an enemy. Creator Sword’s accelerated Special trigger combined with its ability to neutralize skills that would reduce Byleth’s Special cooldown charge generation means that he is able to ensure that he will activate his Special twice if he can double an opponent that counterattacks him.

Clean Up Duty (Offensive Nuke)

Build by
Creator Sword A Swift Sparrow (2 or 3)
Alternate: Atk/Spd Solo 3
Reposition B Windsweep 3
Alternate: Watersweep 3
Ruptured Sky
Alternate: Galeforce
C Savage Blow 3
Alternate: Def Smoke 3
IVsSDarting Blow 3
Alternate: Flashing Blade 3

Show Explanation/Analysis

Preferred IV: +SPD / -HP or -RES

  • This build is heavily dependent on Byleth being able to double his opponents via raw Speed, so it’s important to stack as much Speed as possible.

Weapon: Creator Sword

  • One interaction with Creator Sword is that it negates the self-imposed penalty of Windsweep/Watersweep that prevents the user from doubling. This means that if Byleth utilizes either of those skills and has enough Speed to naturally double his opponent, he can attack them as if he were utilizing a significantly stronger Firesweep Sword.

Assist: Reposition

Special: Ruptured Sky / Galeforce

  • Ruptured Sky is a strong, low cooldown Special that Byleth can easily activate every combat if he doubles his opponent.

  • Alternatively, Byleth can utilize either Flashing Blade or Heavy Blade to help activate Galeforce. Being able to activate Galeforce while simultaneously denying his opponent from counterattacking can make Byleth quite a potent offensive threat.

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

  • Since this build revolves around denying enemies from counterattacking with Windsweep/Watersweep, it’s important to stack as many offensive stat boosts as possible on Byleth. Swift Sparrow 3 and Atk/Spd Solo give massive amounts of offensive stats if available, but otherwise most of the other, more accessible skills like Swift Sparrow 2, Life and Death, or Fury will work.

Passive B: Windsweep / Watersweep

  • This is the key to this build, as the interaction between Windsweep/Watersweep and Creator Sword uniquely allows Byleth to be an incredibly safe and potent offensive nuke. Windsweep is generally a bit better since Byleth is far more likely to get counterattacked by those unit types compared to those covered by Watersweep.

Passive C: Savage Blow / Def Smoke / Pulse Smoke / Odd Spd Wave

  • Byleth’s C skill isn’t particularly important to this build, and is therefore mostly dependent on player preference. Savage Blow and Smoke skills are all synergistic with Galeforce setups, while Byleth’s base Odd Spd Wave will work just fine with any setup if he doesn’t have buff support from his team.

Sacred Seal: Darting Blow / Flashing Blade / Heavy Blade

  • Darting Blow is fantastic when paired with Ruptured Sky for this build, since the big Speed boost will greatly enhance Byleth’s ability to double his opponents.

  • If utilizing a Galeforce build, then either the Flashing Blade or Heavy Blade Seal is a must to help ensure that Byleth can charge up Galeforce.


Byleth enjoys the benefits of a fantastic statline, though he does have a notable weakness in his fairly low Resistance (which is particularly detrimental in Aether Raids, especially considering that he is a red unit). However, the most significant draw to Byleth is the weapon he shares with his female counterpart, the Creator Sword. 

The Creator Sword has three separate effects that individually are all quite significant (though the Slaying effect is hardly a new one and not particularly impressive alone), but combined, turns Byleth into an incredibly versatile and powerful unit capable of completely ignoring most conventionally powerful setups. It allows him to be one of the first units to ever be able to utilize both Null Follow-Up and Null C-Disrupt at the same time, which grants him the ability to single-handedly deal with the vast majority of threats in Aether Raids defense setups.

It’s worth noting that while Byleth is incredibly versatile, he does have notable weaknesses that prevent him from simply being the best unit in the game. For example, being a red unit with poor Resistance makes him extremely vulnerable to some very popular blue magical damage nukes like Ophelia and Reinhardt (though this can also be dealt with with proper setup). Overall, Byleth is a fantastic unit that can greatly assist in one’s Aether Raids runs, and is also a nice treat for picking up Fire Emblem: Three Houses.


Creator Sword

Byleth’s weapon is his single most defining and powerful feature. Having Null Follow-Up built into his weapon gives him fantastic skill versatility, including the ability to combine Null Follow-Up with Null C-Disrupt. Combining this with the accelerated Special trigger and negating enemy skills that either accelerate their Special charge generation or reduce Byleth’s Special charge generation makes him a highly versatile unit that is very difficult to counter through conventional means.

Strong Offenses

36/38 Attack/Speed is a very powerful offensive spread, and having access to +4 instead of +3 with a +SPD Asset is just icing on Byleth’s cake. His statline is very well suited to utilizing his Creator Sword.


Poor Resistance

Byleth’s weakest stat is easily his Resistance, which is particularly detrimental if utilizing him in Aether Raids, where magical damage is extremely prevalent. His status as a red unit is even more troublesome because he has a very difficult time dealing with common blue magical damage threats like Ophelia and Reinhardt.

Vulnerable to Debuffs

Byleth can potentially face some serious issues with strong Aether Raids defense setups because he can easily be outsped by units like Legendary Alm thanks to the intervention of a variety of debuffs. His strong offensive stat spread makes him very liable to get targeted by both Chill Atk and Chill Spd, and the newly introduced Lull skills (such as Lull Spd/Def) can make it extremely difficult for Byleth to keep up.

Weapon Skills

Weapons SP Rng. Mt.
Iron Sword
Learns by default at 1 ★
Unlocks at 1 ★
Only Inheritable by Sword Units.
50 1 6
Steel Sword
Learns by default at 3 ★
Unlocks at 2 ★
Only Inheritable by Sword Units.
100 1 8
Silver Sword
Learns by default at 4 ★
Unlocks at 3 ★
Only Inheritable by Sword Units.
200 1 11
Creator Sword

Accelerates Special trigger (cooldown count-1).

During combat, neutralizes effects that guarantee foe's follow-up attacks, prevent unit's follow-up attacks, grant "Special cooldown charge +X" to foe, or inflict "Special cooldown charge -X" on unit.

Learns by default at 5 ★
Unlocks at 5 ★
Non-Inheritable skill.
400 1 16
Available Rearmed Weapons
Arcane Devourer
Arcane Éljúðnir
Weapon Evolution
Weapon Upgrades
Weapon Upgrades

Special Skills

Special Skills SP Turns
Draconic Aura

Boosts damage by 30% of unit's Atk.

Learns by default at 4 ★
Unlocks at 3 ★
Non-inheritable by Staff-wielding units.
200 3
Ruptured Sky

Boost damage by 20% of foe's Atk. If in combat against dragon foe or beast foe, boost damage by 40% instead of 20%.

Unlocks at 5 ★
Excludes Staff, Dragon and Beast Units
500 2

Passive Skills

Passive Skills SP Slot
Distant Counter

Unit can counterattack regardless of foe's range.

Restricted to melee units.
Unlocks at 5 ★
Chill Spd 1

At start of turn, inflicts Spd-3 on foe on the enemy team with the highest Spd through its next action.

Inheritable by all units.
Unlocks at 3 ★
Chill Spd 2

At start of turn, inflicts Spd-5 on foe on the enemy team with the highest Spd through its next action.

Inheritable by all units.
Unlocks at 4 ★
Chill Spd 3

At start of turn, inflicts Spd-7 on foe on the enemy team with the highest Spd through its next action.

Inheritable by all units.
Unlocks at 5 ★
Odd Spd Wave 1

At start of odd-numbered turns, grants Spd+2 to unit and adjacent allies for 1 turn.
(Bonus granted to unit even if no allies are adjacent.)

Inheritable by all units.
Unlocks at 1 ★
Odd Spd Wave 2

At start of odd-numbered turns, grants Spd+4 to unit and adjacent allies for 1 turn.
(Bonus granted to unit even if no allies are adjacent.)

Inheritable by all units.
Unlocks at 2 ★
Odd Spd Wave 3

At start of odd-numbered turns, grants Spd+6 to unit and adjacent allies for 1 turn.
(Bonus granted to unit even if no allies are adjacent.)

Inheritable by all units.
Unlocks at 4 ★

Other Info

Fire Emblem: Three Houses

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