Mydei
O Chrysos Heir · King of Kremnos
S+ TIER DPSOne Must Slay a God to Become One
Mydei is a 5-star Imaginary Destruction character and one of the most unique DPS units in Honkai: Star Rail. Unlike conventional carries, he scales entirely off Max HP—both his Skill damage and survivability grow as his HP pool increases. His core loop is a berserker fantasy: he sacrifices his own HP to charge his Talent (Blood for Blood), and at 100 Charge he enters the fearsome Vendetta state—a transformation that resets his HP, increases his Max HP by 50%, drops his DEF to zero, and begins automatically unleashing his Enhanced Skill “Kingslayer Be King” on every turn.
At 150 Charge during Vendetta, he consumes it for an immediate extra turn and triggers “Godslayer Be God”—a devastating multi-target Imaginary nuke based on Max HP. His Ultimate “Throne of Bones” restores HP, grants 20 Charge, taunts nearby enemies, and marks a priority target for the next Godslayer hit. Crucially, his Trace “Earth and Water” prevents him from being knocked out in Vendetta state (up to 3 times per battle), and “Bloodied Chiton” converts his massive HP pool directly into CRIT Rate—making him remarkably low-maintenance to stat-check. Stack HP, enter Vendetta, and watch gods fall.
Mydei released in Version 3.1 alongside Tribbie and remains a dominant hypercarry through Version 4.0. His self-sustaining mechanics, built-in pseudo-revive, and HP-scaling damage make him ideal for both new players seeking a durable main DPS and veterans wanting top-end single-target destruction.
Best Light Cones
Flame of Blood, Blaze My Path
⭐⭐⭐⭐⭐ Signature · BISUndisputed Best-in-Slot. Grants +18% Max HP and +20% Incoming Healing—both critical for Mydei’s kit. When using Skill or Ultimate, consumes 6% of Max HP and increases that attack’s DMG by 30%. If HP consumed exceeds 500, an additional 30% DMG boost applies (60% total). This synergizes perfectly with Mydei’s HP-drain loop: every skill use accelerates Charge accumulation while simultaneously boosting damage. The healing bonus ensures he recovers more per heal cycle, sustaining longer Vendetta states. Pull this alongside him if possible—it transforms his ceiling significantly.
The Unreachable Side
⭐⭐⭐⭐⭐ Blade’s LC · Strong AltExcellent 5-star alternative from the standard banner. Grants +18% CRIT Rate and +18% Max HP. Whenever Mydei is attacked or consumes his own HP, his DMG increases by 24% (removed after the next attack). With constant HP consumption, this buff has near-permanent uptime during Vendetta. The CRIT Rate also dramatically reduces relic pressure. Best non-signature option for players who already own this cone.
Ninja Record: Sound Hunt
⭐⭐⭐⭐ Event LC · Best 4-StarTop 4-star choice. Grants +12% Max HP. When losing or restoring HP, increases CRIT DMG by 18% for 2 turns. Given Mydei’s constant HP fluctuation—draining HP via skills and restoring via Vendetta entry and Ultimate—this buff maintains excellent uptime. Since Mydei’s stat build emphasizes CRIT DMG over CRIT Rate (due to Bloodied Chiton trace), this cone slots perfectly into that priority. Obtainable from events; worth superimposing.
Flames Afar
⭐⭐⭐⭐ Memory of Chaos ShopSolid F2P option purchasable from the Memory of Chaos shop. When cumulative HP loss during one attack exceeds 25% of Max HP, heals the wearer and increases DMG% for a duration. Mydei’s Skill regularly exceeds this threshold, activating both effects consistently. Provides a self-sustain layer on top of damage amplification. A reliable stop-gap until better options are acquired.
Best Relics & Ornaments
🥇 4-Piece: Scholar Lost in Erudition (BiS)
Best-in-Slot for Mydei—particularly in Sunday compositions. Since virtually all of Mydei’s damage comes from Skill (Kingslayer Be King / Godslayer Be God) and Ultimate (Throne of Bones), the 20% universal amplifier is always active. The post-Ultimate 25% Skill bonus rewards proper rotation: Ultimate → Enhanced Skill → massive damage spike. The 2-piece CRIT Rate also reduces stat pressure from relics.
🥈 4-Piece: Longevous Disciple (Alt)
Strong alternative that leans into HP scaling. The Max HP bonus directly amplifies Mydei’s damage multipliers and improves his Bloodied Chiton CRIT Rate conversion. The 4-piece CRIT Rate stacks rapidly given constant HP consumption and enemy attacks, providing near-permanent +16% CRIT Rate during combat. Best choice if you have exceptional substats on these pieces or prefer HP-forward stat distribution.
🌐 Planar Ornaments
📊 Target Stats (Recommended)
Main Stats: Head = HP% | Hands = HP% | Body = CRIT DMG (preferred) or CRIT Rate | Boots = SPD or HP% | Sphere = HP% (reach 8k threshold) or Imaginary DMG% | Rope = HP%
Priority: Reach 8,000+ Max HP first (activates max Bloodied Chiton CRIT Rate bonus of ~48%), then focus on CRIT DMG. Mydei generates a large portion of his CRIT Rate from his Bloodied Chiton trace—so stack CRIT DMG heavily in substats.
Trace Priority
- Skill (Deaths are Legion, Regrets are None): Mydei’s primary HP drain and damage source. Every level increases the Skill’s HP-based damage multipliers and powers up Kingslayer Be King / Godslayer Be God during Vendetta. Always max first—this is where 80%+ of his total damage originates.
- Ultimate (Throne of Bones): Restores HP, grants 20 Charge, taunts, and marks priority targets. Higher levels improve HP restoration and damage. Essential for maintaining Vendetta loops and directing Godslayer hits. Max second.
- Talent (Blood for Blood): Controls Charge accumulation rate from HP loss. Higher talent levels improve the ratio of Charge gained per HP% lost, enabling faster Vendetta entry and more frequent Godslayer activations. Critical for rotation speed—prioritize after Skill and Ultimate.
- Basic ATK (Vow of Voyage): Lowest priority. Mydei should almost never use his Basic ATK in optimal gameplay—Skill spam is always preferred for HP drain, Charge gain, and damage output.
🩸 Key Bonus Abilities (Traces)
Bloodied Chiton (A6 – Critical): For every 100 Max HP above 4,000, Mydei gains +1.2% CRIT Rate, +2.5% Charge ratio from enemy attacks, and +0.75% Incoming Healing. Up to 4,000 HP counts (i.e., 8,000 total HP = max benefit). At 8,000 HP, this grants approximately +48% CRIT Rate passively—the cornerstone of his entire build philosophy.
Earth and Water (A4 – Survival): Prevents Mydei from being knocked out when receiving a fatal blow while in Vendetta state. Instead, he restores 50% Max HP and continues fighting. Triggers up to 3 times per battle—effectively granting him three extra lives during his power state.
Thirty Tyrants (A2 – Control Immunity): While in Vendetta state, Mydei is immune to all Crowd Control effects. Ensures his automated Enhanced Skill sequence cannot be interrupted by stuns, freezes, or imprisons.
Eidolons
E1 – The Undying King ⭐ Strong
Buffs the damage of Godslayer Be God significantly, and in multi-target situations turns Mydei into an AoE powerhouse comparable to Erudition characters. E1 is a notable quality-of-life and damage improvement—especially valuable in Pure Fiction and Apocalyptic Shadow stages with multiple enemies. Worth considering if you enjoy the character.
E2 – Blood of the Conqueror 🌟 Major Power Spike
Allows damage dealt during Vendetta to partially ignore enemy DEF—a multiplicative damage increase that bypasses one of the biggest defensive walls in endgame content. Additionally converts incoming healing into Charge, accelerating the Vendetta loop by generating Charge passively whenever healed. This Eidolon dramatically raises both his damage ceiling and loop frequency. Widely considered the most impactful Eidolon after E0.
E4 – Iron Will of the Lion
Increases CRIT DMG during Vendetta state and restores some HP whenever Mydei is struck by an enemy. Improves both survivability and damage amplification within his power state. A solid incremental upgrade that rewards tanking hits and remaining in Vendetta as long as possible.
E6 – God Among Gods
Mydei automatically enters Vendetta state at the start of combat, bypassing the initial Charge ramp. Additionally reduces the Charge cost of Godslayer Be God from 150 to 100, allowing it to trigger far more frequently. Combined with E2’s healing-to-Charge conversion, E6 Mydei maintains near-continuous Vendetta with godslaying frequency. Endgame whale territory—but absolutely spectacular in action.
💡 Eidolon Pull Priority
E0 is excellent and fully functional. Mydei’s base kit is complete and strong without Eidolons. If investing further, E1 is a meaningful damage and AoE upgrade for multi-enemy content. E2 is his most impactful Eidolon—the DEF-ignore and heal-to-Charge conversion are game-changing for both damage and loop speed. Beyond E2, returns are incremental until the dramatic E6 transformation.
Best Team Compositions
👑 Premium Hypercarry (Cyrene + Cerydra)
The bleeding-edge team composition for Mydei in Version 4.0. Cyrene converts teammates’ actions into additional Ultimate damage triggers, maximizing burst potential in high-speed rotations—every support action generates extra Godslayer procs. Cerydra provides precise control over burst timing, turning Mydei’s previously unpredictable HP-based bursts into strategically timed damage windows. Hyacine sustains the team while working in conjunction with Cyrene to maintain fast action cycles. As a Chrysos Heir, Hyacine can also directly increase Mydei’s HP, elevating his Bloodied Chiton CRIT Rate bonus. This team is the current benchmark for Mydei’s peak performance.
☀️ Sunday Hypercarry (Classic Premium)
Mydei’s most potent classic hypercarry setup. Sunday is Mydei’s ideal first support—providing massive CRIT DMG buffs (80%+), 100% action advance, energy restoration, and ensuring Godslayer hits the correct priority target. More turns mean more HP consumption, faster Charge accumulation, and more frequent Godslayer activations. Tribbie applies All-Type RES penetration and triggers additional attacks after teammates’ Ultimates. Huohuo provides consistent team-wide heals and energy restoration—critical for keeping Mydei’s HP cycles and Vendetta uptime healthy. This team dominated Memory of Chaos throughout 3.x patches.
🌸 Sparkle/RMC Hypercarry (Accessible)
A strong accessible alternative for players without Sunday. Sparkle delivers 50% action advance, massive CRIT DMG buffs, and SP economy—enabling Mydei to spam Skills without running dry. Ruan Mei provides universal DMG%, SPD boost, and RES PEN—her buffs are completely team-agnostic and enhance Mydei’s output reliably. Luocha is Mydei’s preferred healer here—his automatic passive healing triggers off any ally action and his Abyss Flower field provides sustained recovery, perfectly complementing Mydei’s constant HP drain.
⚗️ Sub-DPS Castorice Support
An interesting niche use-case where Mydei serves as Sub-DPS for Castorice. Mydei’s constant HP consumption naturally builds Newbud stacks for Castorice’s Ultimate, creating a synergistic HP-drain loop. Tribbie buffs both Mydei and Castorice simultaneously with resistance penetration. Gallagher provides Besotted debuff for constant healing application. While Mydei performs better as main DPS, this composition demonstrates his team flexibility.
🆓 F2P Accessible Team
A fully accessible team requiring no limited 5-star supports. Remembrance Trailblazer (RMC) provides CRIT DMG buffs and summons Mem—a free source of additional buffs that stacks well with Mydei’s CRIT DMG-heavy build. Pela is SP-positive, applies DEF shred consistently, and keeps buffs cycling efficiently. Gallagher heals and applies the Besotted debuff. This team is surprisingly competitive and is the recommended starting point for new players building Mydei.
Gameplay Tips & Rotation
Core Rotation & Vendetta Loop
Mydei’s rotation is intuitive once the Vendetta loop is understood:
- Pre-Vendetta: Spam Skill (Deaths are Legion) to drain HP rapidly and accumulate Charge. Each Skill drains 50% current HP and generates substantial Charge.
- Use Ultimate (Throne of Bones) when available—it restores HP (resetting the drain cycle), grants 20 Charge, taunts, and marks the priority target for Godslayer.
- At 100 Charge, Vendetta activates automatically: HP restores, Max HP increases by 50%, action advances 100%, and Kingslayer Be King fires every turn.
- During Vendetta, continue accumulating Charge. At 150 Charge, Godslayer Be God triggers with an extra turn—aim this at the priority target marked by Ultimate.
- Use Ultimate during Vendetta to maintain HP and recharge the loop. Cycle repeats.
💡 Mydei Pro Tips
HP threshold first: Prioritize reaching 8,000+ Max HP before optimizing CRIT stats. Below the threshold, Bloodied Chiton underperforms and your damage ceiling drops significantly.
Don’t run two action-advance supports: Running Sunday AND Sparkle simultaneously causes Mydei to act so frequently that his HP drains dangerously fast, increasing the risk of exiting Vendetta from low HP spikes. One action-advance support is optimal.
Luocha vs Lingsha: Luocha’s passive healing field and emergency skill heal synergize better with Mydei’s constant HP fluctuation than most healers. Gallagher and Huohuo are also strong alternatives—avoid burst-heal-only characters who can’t sustain continuous recovery.
Godslayer target priority: Use Ultimate before Godslayer activates to mark the strongest enemy as priority target—this focuses all three Enhanced Skill hits and the finisher where it matters most.
Vendetta entry timing: If a healer’s turn is coming soon, consider holding your last Skill use so the heal resets your HP before Vendetta—entering Vendetta at higher HP means a larger Max HP bonus (50% of a higher base).
Mydei vs Other Top DPS
vs Blade (Wind HP DPS)
Both are HP-scaling Destruction DPS with self-drain mechanics—but Mydei is a significant upgrade in every dimension. His HP-to-damage multipliers are higher, his Vendetta state provides more burst potential than Blade’s Hell Flutter, and his three-lives mechanic in Vendetta vastly outclasses Blade’s single-threshold survival. Blade still has value in DoT/follow-up compositions, but Mydei strictly supersedes him as the premier HP-based DPS.
vs Phainon (Wind Destruction)
Phainon is a newer S+ tier Destruction unit with exceptional single-target output, while Mydei leans toward burst AoE from Godslayer Be God. Phainon excels with Sunday in precision hypercarry scenarios; Mydei performs better when paired with Cyrene/Cerydra for controlled burst timing. Both are top-tier—team availability and content type determine which shines brighter.
vs Firefly (Fire Break DPS)
Firefly dominates Break-centric compositions built around Ruan Mei and Harmony Trailblazer. Mydei has no reliance on Break mechanics and performs consistently against non-breakable or highly toughened bosses. In raw boss-killing scenarios, Mydei’s Vendetta burst rivals Firefly’s Break damage, while Firefly has the edge in multi-wave content with exploitable Weaknesses.
Should You Pull Mydei?
✅ Absolutely Pull Him if:
- You want a durable, self-sustaining main DPS who doesn’t need a dedicated healer every team
- You have Sunday, Sparkle, or Cyrene for premium team support
- You enjoy HP-consumption berserker gameplay with dramatic Vendetta transformation
- You lack a strong Imaginary DPS and want a future-proof investment
- You’re a new or returning player—his straightforward stat requirements (stack HP, CRIT DMG) make him beginner-friendly
⚠️ Consider Carefully if:
- You already have Phainon or Feixiao with invested teams and limited resources
- You lack premium healing support—Mydei’s constant HP drain requires reliable heal cycling
- You dislike auto-controlled gameplay (Vendetta automated attacks can feel uncontrollable)
Final Verdict: Mydei is an S+ tier hypercarry who has maintained dominance from Version 3.1 through 4.0. His unique HP-scaling design, self-sustaining three-lives mechanic, and dramatic Vendetta transformation make him one of the most satisfying and powerful DPS units in the game. His stat requirements are refreshingly simple—stack HP to 8,000+, stack CRIT DMG—making him accessible to players who struggle with complex relic farming. With the right supports, he is a legitimate top-three DPS in the current meta. Whether you’re a new player or a veteran seeking another powerhouse, Mydei is an outstanding long-term investment.