Firefly Build Guide 2026: Best Relics, Light Cones & Break Team Guide

Complete Firefly build guide updated for version 4.x. Covers Iron Cavalry relics, F2P light cones, Super Break teams, and stat benchmarks for maximum damage.

Overview

Firefly is a 5★ Fire Destruction DPS who specializes in the Super Break playstyle. She enters a Complete Combustion state via her ultimate, applies Fire Weakness to enemies, and deals massive break damage.

She remains one of the best investments in the game, excelling in Memory of Chaos and Apocalyptic Shadow.

Role: Main DPS Rarity: 5★ Element: Fire Path: Destruction

F2P Verdict: ✅ Excellent. She has a free 5-star light cone from Herta's Store, free best teammates (Harmony Trailblazer, Gallagher), and doesn't need crit stats — making her one of the easiest characters to build.

How Her Kit Works (Simple Explanation)

Ultimate: Transforms into Complete Combustion state. Applies Fire Weakness to enemies. All damage becomes Super Break damage.
Skill: Deals AoE Fire DMG. In combustion state, recovers HP instead of consuming skill points.
Talent: Reduces enemy Toughness more efficiently after breaking.
A6 Trace: Converts ATK over 1800 into Break Effect (every 10 ATK = 0.8% BE).

Key takeaway: Stack Break Effect and Speed. Ignore crit stats completely.

Best Relic Sets

4-Piece: Iron Cavalry Against the Scourge ★★★★★ (Best in Slot)

Bonus	Effect
2-Piece	Break Effect +16%
4-Piece	If Break Effect ≥ 150%, ignore 10% DEF. If ≥ 250%, Super Break ignores an additional 15% DEF.

This is undeniably her best set — farm it without hesitation.

Alternative: 2-Piece Iron Cavalry + 2-Piece Thief of Shooting Meteor

Use this hybrid while farming a good 4-piece Iron Cavalry
Only ~3-5% worse

Fallback: 4-Piece Thief of Shooting Meteor

Break Effect +16% (2pc) + Energy regeneration on break (4pc)
Decent early-game option

Planar Ornaments

Set	Verdict
Forge of the Kalpagni Lantern ★★★★★	Best in slot. +6% SPD. When hitting Fire Weak enemy, +40% Break Effect.
Talia: Kingdom of Banditry ✅ F2P	+16% Break Effect. +20% more if SPD ≥ 145. Good while farming Forge.
Firmament Frontline: Glamoth	+12% ATK. Only use if you somehow have great stats already.

Main Stats & Substats

Stat Priority

Piece	Main Stat	Priority
Body	ATK%	★★★★★
Feet	SPD	★★★★★
Planar Sphere	ATK%	★★★★★
Link Rope	Break Effect%	★★★★★

Substats Priority

Break Effect (up to 360% in battle)
SPD (up to 145-160 breakpoints)
ATK%
HP% / DEF% (survival)

❌ Do not build CRIT Rate or CRIT DMG. Firefly's damage doesn't crit.

Stat Breakpoints

Stat	Target	Notes
Break Effect	360% in battle	Maxes out A4 trace bonus (150% Super Break DMG)
SPD	145+ (out of combat)	Hitting 160 is great but not required
ATK	3400+ (out of combat)	More ATK = more conversion to BE via A6 trace

Best Light Cones

Premium Options

Light Cone	Rarity	Note
Whereabouts Should Dreams Rest	5★	Signature — +60% BE, inflicts Routed (+24% Break DMG taken)
On the Fall of an Aeon	5★	Herta's Store — best F2P option

F2P Options ✅

Light Cone	Source	Verdict
On the Fall of an Aeon (S5) 🏆	Herta's Store	Best F2P option. Stacking ATK% + DMG% on break. Free!
Indelible Promise	Battle Pass	+28% BE. The CRIT Rate is wasted, but BE is valuable.
A Secret Vow	Gacha (4★)	+DMG% against enemies with higher HP%. Decent placeholder.
Flames Afar	Gacha (4★)	ATK% boost. Workable early on.

Tip: On the Fall of an Aeon from Herta's Store is genuinely excellent on Firefly. Don't feel pressured to pull her signature LC.

Trace Priority

Trace	Priority	Why
Ultimate	★★★★★	Enables her entire playstyle
Talent	★★★★★	Break efficiency and damage
Skill	★★★★	Secondary damage source
Basic ATK	★★★★	Used less often, but still part of rotation

All 3 Bonus Abilities (A2, A4, A6) are mandatory — unlock them immediately.

Best Team Compositions

Premium S-Tier Team

Role	Character	Notes
DPS	Firefly	—
Support	The Dahlia	New S-tier break enabler
Support	Fugue / Ruan Mei	Super Break + Break efficiency
Sustain	Lingsha / Gallagher	Break synergy healer

F2P A-Tier Team ✅

Role	Character	How to Get
DPS	Firefly	Limited banner
Support	Harmony Trailblazer	✅ Free — Super Break enabler
Support	Asta	✅ Free — SPD buff + break efficiency
Sustain	Gallagher	✅ Free — excellent break healer

Budget Team

Role	Character	How to Get
DPS	Firefly	Limited banner
Support	Harmony Trailblazer	✅ Free
Support	Pela	✅ Free — DEF shred
Sustain	Lynx / Natasha	✅ Free

Eidolons Worth

Eidolon	Worth It?	Note
E0	✅✅ Must-have	Already complete at E0
E1	✅ Yes	15% DEF ignore during ultimate
E2	✅ Yes	Action advance after using skill — big QoL
E6	❌ Not for F2P	Extreme damage amp — overkill for all content

Recommendation: E0 is excellent. E1-E2 are nice but skip if you're saving for other characters.

Game Mode Performance

Mode	Rating	Notes
Memory of Chaos (MoC)	★★★★★	S-tier. Break DPS shines here.
Pure Fiction (PF)	★★★	B-tier. Fewer tanky enemies to break.
Apocalyptic Shadow (AS)	★★★★★	S-tier. Break mode is made for her.

F2P Quick Build Summary

Relic Set:     4-pc Iron Cavalry Against the Scourge
Planar Set:    Forge of the Kalpagni Lantern
Light Cone:    On the Fall of an Aeon (S5, Herta's Store)
Main Stats:    ATK% / SPD / ATK% / Break Effect%
Substats:      Break Effect > SPD > ATK%
Team:          Firefly + HMC + Asta + Gallagher

Final Verdict

Should you pull Firefly as a F2P / light spender?

Absolutely yes. Firefly is one of the most F2P-friendly 5-star DPS units in the game. She has:

A free best-in-slot light cone (Herta's Store)
Free best teammates (Harmony Trailblazer, Gallagher)
No need for crit stats (easiest relic farming in the game)
Dominant performance in two of three endgame modes

Rating: 9.5/10 — pull recommendation: ✅ Strong Yes