Mortenax Blade
Situational—Mortenax Blade is a Fire Nihility debuffer; pull for DoT/Break flex. Ultimate “Fornax Ex Corpore” deploys a team Zone with RES PEN / Break-oriented amp. Best with Kafka / Firefly / Acheron. Nihility support piece—check EHR and archetype fit. Skip when Jiaoqiu/Fugue/Cipher already staff Nihility slots. Nihility support piece — check EHR and archetype fit.
Mortenax Blade is a 5★ Fire Nihility Debuffer. Skill “A Rain of Blades Seals Fate” is the primary in-combat spend. Ultimate “Fornax Ex Corpore” is the payoff window for damage or team utility. This Phase 1 page covers kit text, gear targets, and pull notes—team comps stay empty until Phase 2.
Overview
Quick Build
Light Cone
Reforged in Hellfire
Signature BiS when owned.
Relic Set
Pioneer Diver of Dead Waters (4pc) + Pan-Cosmic Commercial Enterprise (2pc)
Standard Nihility relic direction for Mortenax Blade.
Body
Effect Hit Rate
Main stat
Feet
SPD
Main stat
Sphere / Rope
Fire DMG% · ATK%
Substats
EHR (to threshold) > SPD > ATK% / CRIT
Strengths
- Ultimate “Fornax Ex Corpore” spends HP as a deliberate self-damage cost—level this before polishing filler traces.
- Skill “A Rain of Blades Seals Fate” spends HP as a deliberate self-damage cost—the rotation wants controlled self-damage, not panic healing that cancels the state.
- Talent “All Karma Comes Due” fires Follow-Up ATKs off ally Basics—damage keeps flowing even when Mortenax Blade is not the active turn.
- DEF shred from “Fornax Ex Corpore” multiplies every ally’s damage for the duration—Mortenax Blade is doing amp work, not only personal DPS.
Weaknesses
- Follow-Ups from “All Karma Comes Due” need allies who actually Basic ATK on schedule—freeze/CC on the team stalls Mortenax Blade’s off-turn damage.
- HP-spend skills mean Mortenax Blade can soft-lock if sustain is weak or if a healer tops them up at the wrong time and breaks a low-HP / Charge condition.
- Spamming “A Rain of Blades Seals Fate” every turn without watching Skill Points strands the rest of the team—Mortenax Blade is often the SP sink.
- If “Fornax Ex Corpore” is still offline at the end of a MoC cycle, the build is usually Energy/ERR or rotation order—not a missing CRIT roll.
Trace Priority
A Rain of Blades Seals Fate carries most of the kit’s damage or utility—level this first.
Fornax Ex Corpore supports the main rotation—raise after the top priority traces.
All Karma Comes Due supports the main rotation—raise after the top priority traces.
A Broken Blade Still Slays is last priority outside of filling trace materials.
Stat Priority
Open with Technique if it helps, spend Skill to advance the kit’s resource, and hold Ultimate for the damage or buff window. Exact teammate order lands in Phase 2.
Open supports first, then spend the carry’s Skill/Ult inside the buff window. Exact order varies by the team tab above.
Light Cones
5★ · Path cone
Increases the wearer's Max HP by 0.3%. At the start of the wearer's turn, regenerates a fixed amount of 20 Energy. This effect can trigger 1 time each wave. After the wearer uses Skill to attack, inflicts the target with the "Purgatory" state, lasting for 2 turn(s). While in the "Purgatory" state, the target receives 0.3% increased CRIT DMG and 0.3% additionally increased CRIT DMG from the wearer.
Why it works —Signature / best-in-slot when owned—passive lines up with Mortenax Blade’s kit triggers.
5★ · Path cone
Increases the wearer's Effect Hit Rate by 0.24%. When the wearer deals DMG to an enemy that currently has 3 or more debuffs, increases the wearer's CRIT Rate by 0.12%. After the wearer uses their Basic ATK, Skill, or Ultimate, there is a 1% base chance to implant Aether Code on a random hit target that does not yet have it. Targets with Aether Code receive 0.12% increased DMG for 1 turn.
Why it works —Flexible alternative on the same path—equip if you already own it at higher superimposition.
4★ · Path cone
For every debuff the target enemy has, the DMG dealt by the wearer increases by 0.12%, stacking up to 3 time(s). This effect also applies to DoT.
Why it works —Best accessible option for most accounts—raise superimposition when copies drop.
4★ · Path cone
Increase the wearer's CRIT Rate by 0.08%. The wearer deals 0.24% more CRIT DMG to enemies that are currently Slowed or have reduced DEF.
Why it works —Budget path cone—fine while building the account.
Relics
Team Compositions
Mortenax Blade enabling Himeko · Nova. Himeko · Nova, Sunday, Dan Heng · PT complete the remembrance shell.
Himeko · Nova is the damage seat in this shell — build the supports around their rotation, not the reverse.
Enabler / amp piece this page is built around — keep their buffs or debuffs online every cycle.
Sunday is the Advance / DMG amp — time their Skill/Ult for the carry’s damage window.
Dan Heng · PT shields the hypercarry and softens MoC / AS chip so glass DPS can commit to Skill spam.
Traces & Eidolons
Traces
Deals Fire DMG equal to 70% of Mortenax Blade's Max HP to one designated enemy, and causes the target to enter the Taunt state for 1 turn.
Consumes HP equal to 10.0% of Mortenax Blade's Max HP and deals Fire DMG equal to 90% of Mortenax Blade's Max HP to all enemies, and additionally deals 4 instance(s) of DMG, with each instance dealing Fire DMG equal to 30.0% of Mortenax Blade's Max HP to one random enemy. If the current HP is insufficient, Mortenax Blade's current HP will be reduced to 1 when he uses Skill. While not in the "Infinite Fury" state or when the current HP is 1 or lower, Mortenax Blade cannot use his Skill. Using Skill does not consume Skill Points.
Inflicts "Balefire Bind" on all enemies. Enemy targets in the "Balefire Bind" state have their DEF reduced by 35.0% and the DMG they receive increases by 60.0%, lasting for 2 turn(s). Then, consumes HP equal to 20% of Mortenax Blade's Max HP to deploy a Zone. While the Zone is active, Mortenax Blade enters the "Infinite Fury" state. During the "Infinite Fury" state, increases CRIT Rate by 20%, increases CRIT DMG by 75.0%, enhances Basic ATK, unlocks Skill, and gains a new Ultimate "Tenax Per Ignem." When receiving a killing blow, this unit will not be knocked down, but will dispel the Zone, exit the "Infinite Fury" state, and restore HP equal to 50% of this unit's Max HP. When gaining the "Infinite Fury" state, a corresponding countdown appears on the Action Order. The countdown has a fixed SPD of 70. At the start of the countdown's turn, dispels the Zone and exits the "Infinite Fury" state. If the current HP is insufficient, Mortenax Blade's current HP will be reduced to 1 when he uses this ability.
While the Zone is active, after each attack an ally target uses on an enemy, inflicts the "Balefire Bind" state on the corresponding enemy target and grants 1 Charge to Mortenax Blade. When Charge reaches 9 points and the current HP is more than 1, consumes 9 Charge, regenerates 30.0 Energy, and enables Mortenax Blade to use Skill 1 extra time. This extra Skill use is considered as Follow-Up ATK.
Immediately attacks all enemies within a certain range. After entering combat, inflicts the Taunt state on all enemies for 1 turn and decreases DMG taken by this unit by 90% for 2 turn(s).
Deals Fire DMG equal to 140% of Mortenax Blade's Max HP to one designated enemy, and causes the target to enter the Taunt state for 1 turn.
Deals Fire DMG equal to 420.0% of Mortenax Blade's Max HP to all enemies.
Eidolons
While the Zone is active, decreases all enemies' All-Type RES by 20%. After using the extra Skill from Talent, the "Infinite Fury" countdown has its action delayed by 15%.
Is it worth getting?
Modest E1: While the Zone is active, decreases all enemies' All-Type RES by 20%. Helpful padding, not a build-defining unlock.
When an ally character uses Ultimate to deal DMG, it is considered as having launched Follow-Up ATK. And the Follow-Up ATK DMG dealt by ally targets increases by 75%. The upper limit of Mortenax Blade's Charge decreases to 7.
Is it worth getting?
Kit add-on: When an ally character uses Ultimate to deal DMG, it is considered as having launched Follow-Up ATK. Evaluate against your supports—pull only if that specific clause solves a problem you actually hit.
Ultimate Lv. +2, up to a maximum of Lv. 15. Talent Lv. +2, up to a maximum of Lv. 15.
Is it worth getting?
Ultimate + Talent levels only (+2). Free if you roll into it; never spend currency aiming for E3.
"Heart, Refined ad Infinitum" additionally increases ally targets' DMG dealt by 50%.
Is it worth getting?
Side-grade: "Heart, Refined ad Infinitum" additionally increases ally targets' DMG dealt by 50%. Happy if it drops; not a planned stopping point.
Skill Lv. +2, up to a maximum of Lv. 15. Basic ATK Lv. +1, up to a maximum of Lv. 10.
Is it worth getting?
Skill + Basic ATK levels only (+2). Skip as a goal—grab it if you overshoot toward E6, never hard-pity for it.
As the Zone persists, when Mortenax Blade takes DMG or consumes HP, he gains 1 Charge. This effect can trigger again after any target's turn ends. The DMG multiplier of "Tenax Per Ignem" increases to 150% of its original value.
Is it worth getting?
Whale ceiling: As the Zone persists, when Mortenax Blade takes DMG or consumes HP, he gains 1 Charge. Only chase if Mortenax Blade is your dedicated Nihility main and E0–E2 already feel finished.
Mortenax Blade is fully usable at E0. Dedicated mains often stop at E0 before chasing higher. First stop: E0. Endgame target: E0.
Alternatives to Mortenax Blade
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