Mortenax Blade Best Build Guide: Relics, Light Cones & Teams | HSR 4.3

If your gameplay philosophy is “lose HP, gain damage, repeat,” then Mortenax Blade fits perfectly. He’s the kind of character who looks risky, plays risky, and somehow still carries fights like it’s nothing.

This guide covers his kit, materials, and build, along with a quick breakdown of his dual-form playstyle and how his support and DPS modes work without accidentally speedrunning your own defeat.

Mortenax Blade Overview

Rarity: 5-Star | Path: Nihility | Type: Fire

Mortenax Blade is a Fire character who has a dual-form kit and performs well both as a support and as a main DPS.

Before using his Ultimate, he can act as a support by deploying a Zone that reduces enemy stats and increases the damage they take, providing strong team-wide utility.

After using his Ultimate, he shifts into a damage-focused state, gaining access to AoE abilities. His kit revolves around consuming his own HP to boost damage, along with enhanced combat effects, allowing him to function as a powerful main DPS with sustained output within his Zone.

 

Mortenax Blade Combat Skills

Basic ATK

A Broken Blade Still Slays

Deals Fire DMG equal to 50% of Mortenax Blade's Max HP to one designated enemy, and causes the target to enter the Taunt state for 1 turn.

A Tempered Blade Severs Souls

Deals Fire DMG equal to 100% of Mortenax Blade's Max HP to one designated enemy, and causes the target to enter the Taunt state for 1 turn.

Skill

A Rain of Blades Seals Fate

Consumes HP equal to 15% of Mortenax Blade's Max HP and deals Fire DMG equal to 72% 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 24% 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 using his Skill. Using Skill does not consume Skill Points.

Ultimate

Fornax Ex Corpore

Inflicts "Balefire Bind" on all enemies. Enemy targets in the "Balefire Bind" state have their DEF reduced by 30% and DMG received increased by 50%, lasting for 2 turn(s). Then, consumes HP equal to 30% of Mortenax Blade's Max HP to deploy a Zone. While the Zone is active, Mortenax Blade enters the "Infinite Fury" state.

While in the "Infinite Fury" state, CRIT Rate increases by 20% and CRIT DMG increases by 60%, unlocks his 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 recover HP equal to 50% of this unit's Max HP.

When entering 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 using this ability.

Mortenax Blade cannot use his Skill when not in the "Infinite Fury" state.

Downed State

An ally will be incapacitated once their HP is reduced to 0.

Tenax Per Ignem

Deals Fire DMG equal to 300% of Mortenax Blade's Max HP to all enemies.

Talent

All Karma Comes Due

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, Mortenax Blade consumes 9 Charge points, regenerates 25 Energy, and uses his Skill 1 extra time. This extra Skill usage does not consume HP and is considered as a Follow-Up ATK.

Technique

Blade's Reach Spares None

Immediately attacks all enemies within range. After entering combat, Taunts the target for 1 turn and decreases DMG taken by this unit by 90% for 2 turn(s).

Bonus Ability

1.Bone, Hardened ad Nauseam

Mortenax Blade can accumulate up to 80 Energy overflow. After using Ultimate, the Energy overflow is cleared and a corresponding amount of Energy is regenerated. When the battle starts or when the Zone is dispelled, if Energy is below 50%, it is immediately regenerated to 50%.

Soul, Tempered ad Mortem

2.Soul, Tempered ad Mortem

While the Zone is active, increases the chance of being attacked by enemies. After being attacked, inflicts the "Balefire Bind" state on the attacker and Mortenax Blade gains 1 Charge.

Heart, Refined ad Infinitum

3.Heart, Refined ad Infinitum

While the Zone is active, DMG dealt by ally targets increases by 50%. If there are other Nihility characters aside from Mortenax Blade in the ally team, Ultimate DMG dealt by ally targets increases by 50%. Otherwise, Follow-Up ATK DMG dealt by ally targets increases by 50%.

Eidolons

1.Ere My Death, I Stood Unmade	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%. Action Delayed: Increases the target's waiting interval before the next action.
2.Ash Was My Heart, Yet the Flame Stayed	Increases DMG dealt by the extra Skill from Talent by 50%. When an ally character uses their Ultimate to deal DMG, it is considered as launching a Follow-Up ATK. While the Zone is active, when other allies use a Follow-Up ATK, Mortenax Blade gains 1 Charge. This effect can be triggered up to 9 time(s), and the trigger count resets at the start of Mortenax Blade's turn or when the Zone is deployed.
3.Across the Shore, Wrath Laid Bare	Ultimate Lv. +2, up to a maximum of Lv. 15. Talent Lv. +2, up to a maximum of Lv. 15.
4.Odium I've Smitten, Thence Came the Blade	"Heart, Refined ad Infinitum" additionally increases ally targets' DMG dealt by 50%.
5.I Severed My Woes, Knowing Death Begets Life	Skill Lv. +2, up to a maximum of Lv. 15. Basic ATK Lv. +1, up to a maximum of Lv. 10.
6.If Immortality Could Die, I Swore THEM Slain	While the Zone is active, when Mortenax Blade takes DMG or consumes HP, he gains 1 Charge. This effect can be triggered again after any target's turn ends. The DMG multiplier of "Tenax Per Ignem" increases to 150% of the original multiplier.

 

Mortenax Blade Signature Weapon

Reforged in Hellfire

Increases the wearer's Max HP by 24%. At the start of each wave, the wearer regenerates 20 Energy. After the wearer uses a Skill Attack, inflicts the target with the "Purgatory" state, lasting for 2 turn(s). While in the "Purgatory" state, CRIT DMG taken by the target increases by 30%, and CRIT DMG taken from the wearer additionally increases by 30%.

 

Mortenax Blade Materials

Check out Mortenax Blade's ascension, skill, and signature weapon materials below — see what you're still short on!

Ascension Materials

Materials	Total
Credit	x 308000
Radiant Prominence	x 65
Whimsy Wax	x 15
Dreamweave Steel	x 15
Lucid Awl	x 15

Skill Materials

Materials	Total
Credit	x 2197500
Tracks of Destiny	x 6
Tear of Phagousa	x 12
Wine of Phagousa	x 53
Heart of Phagousa	x 101
TBA	x 9
Whimsy Wax	x 33
Dreamweave Steel	x 46
Lucid Awl	x 28

Signature Weapon Materials

Materials	Total
Credit	x 385000
Tear of Phagousa	x 4
Wine of Phagousa	x 12
Heart of Phagousa	x 15
Whimsy Wax	x 20
Dreamweave Steel	x 20
Lucid Awl	x 14

 

Mortenax Blade Recommended Light Cones

Best choice: Signature Light Cone

Reforged in Hellfire

Increases the wearer's Max HP by 24%. At the start of each wave, the wearer regenerates 20 Energy. After the wearer uses a Skill Attack, inflicts the target with the "Purgatory" state, lasting for 2 turn(s). While in the "Purgatory" state, CRIT DMG taken by the target increases by 30%, and CRIT DMG taken from the wearer additionally increases by 30%.

Alternative Light Cone

Light Cone	Effect
Lies Dance on the Breeze	Increases the wearer's SPD by 18%. After the wearer uses an attack, there is a 120% base chance to inflict the "Bamboozle" state on every enemy target. While under the "Bamboozle" state, enemy targets have their DEF decreased by 16% for 2 turn(s). If the wearer's SPD is higher than or equal to 170, there is a 120% base chance to inflict the "Theft" state on every enemy target. While under the "Theft" state, enemy targets have their DEF decreased by 8% for 2 turn(s). When "Bamboozle" or "Theft" is repeatedly inflicted, only the most recently inflicted instance takes effect.
Before the Tutorial Mission Starts	Increases the wearer's Effect Hit Rate by 20%. When the wearer attacks DEF-reduced enemies, regenerates 4 Energy.

 

Mortenax Blade Best Relics

4-Pc Selection

Divine-Querying Master Smith	2-Pc: Increases Max HP by 12%.. 4-Pc: Increases the wearer's CRIT DMG dealt to enemy targets in the DEF reduction state by 28%. After the wearer inflicts the DEF reduction state on an enemy target, all allies gain "Comburent" for 2 turn(s). This effect cannot be stacked. DMG dealt by ally targets with "Comburent" increases by 15%. This effect can be triggered again after the wearer uses an attack.
Best-in-slot synergy. He naturally applies DEF reduction and plays around a Zone, so this set amplifies both his personal CRIT DMG and the team’s damage through consistent buffs.
Pioneer Diver of Dead Waters	2-Pc: Increases DMG dealt to enemies with debuffs by 12%. 4-Pc: Increases CRIT Rate by 4%. The wearer deals 8%/12% increased CRIT DMG to enemies with at least 2/3 debuffs. After the wearer inflicts a debuff on enemy targets, the aforementioned effects increase by 100%, lasting for 1 turn(s).
Strong general DPS option. His kit constantly applies debuffs, making it easy to maintain high CRIT Rate and CRIT DMG bonuses against affected enemies.
Longevous Disciple	2-Pc: Increases Max HP by 12%. 4-Pc: When the wearer is hit or has their HP consumed by an ally or themselves, their CRIT Rate increases by 8% for 2 turn(s) and up to 2 stacks.
Very stable pick. He frequently consumes his own HP, so the CRIT Rate stacks are easy to maintain, improving consistency without extra setup.

2-Pc Selection

Bone Collection's Serene Demesne	2-Pc: Increases the wearer's Max HP by 12%. When the wearer's Max HP is 5000 or higher, increases the wearer's and their memosprite's CRIT DMG by 28%.
Simple and efficient. He scales with Max HP, so this directly boosts both survivability and damage, with an extra CRIT DMG bonus at higher HP thresholds.
Inert Salsotto	2-Pc: Increases the wearer's CRIT Rate by 8%. When the wearer's current CRIT Rate reaches 50% or higher, the DMG dealt by the wearer's Ultimate and Follow-Up ATK increases by 15%.
Good offensive option. He can reach the CRIT Rate requirement, and it boosts his Ultimate and follow-up damage, which are key parts of his burst window.

Mortenax Blade Relic Best Stats

Body	CRIT DMG
Feet	SPD
Planar Sphere	Fire DMG Boost
Link Rope	HP
For Sub Stats, Players should aim for this priority: HP＞Crit Rate＞CRIT DMG＞SPD

 

Mortenax Blade Best Team Comp

Mortenax Blade	Ashveil	Tribbie	Dan Heng • PT
Mortenax Blade	Acheron	Sparkle	Cyrene
Mortenax Blade	Tribbie	Sunday	Hyacine

 

Conclusion

Overall, Mortenax Blade is a classic high-risk, high-reward unit. He buffs the team, burns his own HP, then flips into a full AoE damage dealer. Slightly dangerous, very effective.

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