Best Mydei Build, Team and Eidolons HSR 2026

This guide covers the Light Cones, Relics, Trace priority, stat priority, teams, and Eidolon verdicts for the best Mydei build in this guide, along with a full rotation breakdown and my final verdict on whether he’s worth investing into right now.

Mydei is a 5-star Imaginary Destruction unit who turns his own HP into damage, consuming a chunk of his current health every time he uses his Skill and getting stronger for it. He is built to tank hits, taunt the field, and keep swinging without a sustain unit propping him up if you build him right.

TL;DR – Best Mydei Build at a Glance

Best Light Cone	Flame of Blood, Blaze My Path
Best F2P Light Cone Alternative	Ninja Record: Sound Hunt
Best Relic Set	Scholar Lost in Erudition (4pc)
Best Planar Ornament Set	Bone Collection’s Serene Demesne (2pc)
Main Stats	Body: CRIT DMG Boots: SPD Planar Sphere: Imaginary DMG or HP% Link Rope: HP%
Substat priority	HP% > CRIT Rate = CRIT DMG > SPD
Best team (Overall)	Mydei (DPS) Cyrene (Support) Tribbie (Hybrid) Hyacine (Support)
Best team (F2P)	Mydei (DPS) Trailblazer Remembrance (Support) Pela (Support) Lynx (Support)

How to play Mydei: Rotation and Tips

Mydei’s playstyle revolves around a single resource: his own HP. Every Skill, Deaths are Legion, Regrets are None, burns 50% of his current HP to hit one enemy hard and splash the rest, and every point of HP he loses feeds his Talent’s Charge meter. 

Once that meter fills, he enters the Vendetta state, where his Max HP balloons and his DEF drops to zero, and his kit shifts to auto-firing his strongest attacks.

Once Vendetta is active, Kingslayer Be King and eventually Godslayer Be God trigger automatically at the start of his turn, so there’s very little manual sequencing left to manage. 

Just remember to keep his HP topped up enough that he can keep affording his own Skill, and building enough Max HP that his passive CRIT Rate and healing bonuses from Bloodied Chiton stay maxed out.

Best Light Cones for Mydei

Flame of Blood, Blaze My Path is Mydei’s signature and the clear best-in-slot pick. It stacks a large Max HP boost with a DMG bonus that scales the more HP he burns on Skill or Ultimate, on top of a faster Charge-generation mechanic tied directly into his HP-loss gameplay. Skipping it costs a genuinely large chunk of his damage, not a small one.

The Unreachable Side is a strong non-signature alternative if it’s already in your inventory from pulling for Blade. Its CRIT Rate roll overlaps with stats Mydei already gets plenty of from his own kit, but its high Max HP and DMG-on-HP-loss passive still make it a genuinely competitive second option.

A Secret Vow is a solid 4-star pick since Mydei spends a large share of any fight below full HP, which keeps its DMG bonus active for long stretches of a rotation.

For a fully free-to-play option, Ninja Record: Sound Hunt is available from Herta’s Store and pairs well with Mydei’s constant HP swings, since its CRIT DMG buff triggers whenever he loses or restores HP and he can keep that condition active almost every turn.

For a more in-depth look at Mydei’s best Light Cones, visit our Best Mydei Light Cones Guide.

Best Relic and Planar Ornament Sets

Scholar Lost in Erudition is Mydei’s top relic set since the bulk of his damage comes from his Skill, and this set’s bonus rewards exactly that. Time his Ultimate right before Godslayer Be God fires to make sure the set’s follow-up buff is active for it.

Bone Collection’s Serene Demesne is his best Planar Ornament, since most Mydei builds clear its 5,000 HP requirement without any trouble on the way to the 8,000 outside-combat target, and it doesn’t push his CRIT Rate any higher than it already sits.

Mydei’s Stat Priorities

• Priority 1: HP%
• Priority 2: CRIT Rate
• Priority 3: CRIT DMG
• Priority 4: SPD

🎯 Ideal Stat Goals: Aim for 8,000 HP, then target a 134 SPD breakpoint in battle. Flat substats are fine filler once percentage rolls run dry. Mydei’s kit already grants a large chunk of CRIT Rate through Bloodied Chiton once his Max HP crosses 4,000 excess HP, so HP% takes priority early to unlock that bonus before CRIT stats start pulling ahead.

Mydei’s Trace Priorities

Traces	Priority Level	Why?
Basic ATK: Vow of Voyage	Low	Mydei rarely lands on his Basic ATK once Vendetta is running, so this is the last trace worth maxing.
Skill: Deaths are Legion, Regrets are None	Highest	Most of Mydei’s damage comes from his Skill, so this gets maxed first.
Ultimate: Throne of Bones	Highest	His Ultimate deals heavy DMG and taunts the field, and it’s available often enough to matter every cycle.
Talent: Blood for Blood	High	This is what fuels Vendetta and his HP recovery, so it comes right after Skill and Ultimate.
Bonus Ability: Thirty Tyrants	Highest	Grants full Crowd Control immunity during Vendetta, which keeps his rotation from ever getting interrupted.
Bonus Ability: Bloodied Chiton	Highest	This is where his passive CRIT Rate, Charge, and healing bonuses come from once his HP crosses the threshold.
Bonus Ability: Earth and Water	High	Lets him stay in Vendetta through a killing blow instead of getting knocked out of the state.

Mydei’s Ascension Materials (Max Ascension)

Material	Total
Fear-Stomped Flesh	15
Courage-Torn Chest	15
Glory-Aspersed Torso	15
Harbinger of Strife	65
Credit	308,000

Mydei’s Trace Materials (Max Traces)

Material	Total
Borisin Teeth	15
Fear-Stomped Flesh	41
Lupitoxin Sawteeth	72
Courage-Torn Chest	56
Moon Rage Fang	139
Glory-Aspersed Torso	58
Auspice Sliver	12
Tracks of Destiny	8
Credit	3,000,000

Best Mydei Teams (Overall, F2P, and Alternatives)

Listed below are Mydei’s best overall team, F2P team, and alternative teammates to help shape your teambuilding choices based on which units are actually available in your current roster.

Best Overall Mydei Team

Best Mydei Team (Overall)	Role
Mydei	DPS
Cyrene	Support
Tribbie	Hybrid
Hyacine	Support

This team leans on Cyrene, whose Ultimate can trigger Godslayer Be God directly and boost its CRIT DMG, so Mydei stops depending purely on natural HP loss to reach his hardest-hitting attack. 

Tribbie adds damage amplification Mydei’s own kit doesn’t already provide, plus meaningful personal damage thanks to her HP-scaling Trace feeding off his enormous health pool. Hyacine raises his Max HP, which converts to an increase in his damage ceiling, though do note that her healing alone can’t always outpace his self-inflicted HP loss.

Best F2P Mydei Team

Best Mydei Team (F2P)	Role
Mydei	DPS
Trailblazer Remembrance	Support
Pela	Support
Lynx	Support

Trailblazer Remembrance brings action advance and a generic True DMG buff that any F2P roster has access to. Pela shreds enemy DEF with her Ultimate, and Lynx works as a free sustain option, raising Mydei’s Max HP while making it more likely she draws enemy attacks away from squishier teammates.

Best Mydei Team Alternatives

Sparkle is a drop-in replacement for a turn-advance support, letting Mydei run a low, base SPD stat and dump every stat point into CRIT and HP instead while she keeps his tempo up through her own buffs.

Huohuo covers the sustain slot well since her Skill can be used every turn without ever touching Mydei’s own Skill Points, and her healing keeps his HP high enough to keep affording his own Skill cost.

Gallagher is worth running in Apocalyptic Shadow-style content where his kit hits multiple enemies, since his debuffs can land repeatedly whenever Mydei’s Ultimate spreads its Besotted debuff across several targets at once.

Sunday advances Mydei’s turn and restores Energy through his Ultimate, letting Mydei act, and Ultimate, far more often across a fight than he otherwise would.

Bronya is a simpler turn-advance option for players without Sunday or Sparkle built yet, giving Mydei an extra action per use of her Skill.

No matter what character you actually have on your roster, every good alternative for him works the same way: they either advance Mydei’s turn so he lands more Skills and Ultimates, or they keep his HP high enough to keep paying for those attacks without ever putting him in real danger of dropping out of the fight.

Mydei Eidolons: Which Are Worth It

Eidolons	Return on Investment	Explanation
E1: Frost Hones Spine of Steel	Highest	Boosts Godslayer Be God‘s DMG multiplier against the primary target by 30% and extends that same DMG to every other enemy on the field.
E2: Strife Beholds Cry of Dead	High	Lets Vendetta ignore 15% enemy DEF and converts healing Mydei receives into extra Charge.
E3: Honor Exalts Feast of Faith	Low	Only raises Skill and Basic ATK levels, a minor numeric bump with no new effect.
E4: Siren Jolts the Laconic Lion	High	Adds a CRIT DMG buff during Vendetta and restores HP whenever Mydei is hit, both of which push his damage and durability further.
E5: War Chisels Flesh of Flame	Low	Raises Ultimate and Talent levels only, another incremental bump with no new mechanic.
E6: Legacy Scales Mound of Blood	Highest	Puts Mydei into Vendetta the instant he enters battle and lowers the Charge cost of Godslayer Be God.

E1 is the practical stopping point for partial investment, since it’s the single biggest jump in Mydei’s damage output for spenders who don’t plan to chase him all the way to E6.

Verdict: Is Mydei Worth Building in 2026?

Mydei’s Tier Ratings
Overall Rating	S
Endgame Ratings	Memory of Chaos: S Pure Fiction: S Apocalyptic Shadow: A

Though the very top of the meta is currently dominated by newer, more tuned carries, Mydei is still a very strong Destruction damage dealer with excellent damage output, full Death and Crowd Control immunity during Vendetta, and an economy that only gets better the more he’s hit. 

His biggest strength is flexibility. He can be run with a dedicated healer for extra safety, or built to stand entirely on his own once his Bonus Ability Traces are unlocked. If you’re missing a limited Imaginary damage dealer, Mydei is definitely worth pulling and building properly.

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