Honkai: Star Rail Eagle of Twilight Line Relic Set Guide

In Honkai: Star Rail, the four-piece Eagle of Twilight Line relic set advances the wearer’s action by 25% immediately after they cast an Ultimate. Equipping this set on supports and debuffers lowers their raw Speed stat requirements for bonus turns, accelerates Skill Point generation, and maintains continuous debuff uptime in turn-restricted modes like Memory of Chaos.

How the 4-Piece Advance Works

Action order in Honkai: Star Rail is calculated using the formula:

Action Value = 10,000 / Speed

A 25% Action Advance subtracts 2,500 base Action Value from a character's remaining distance to their next turn. Unlike flat percentage Speed buffs, which face diminishing returns and expire over time, an Action Advance cuts directly into the turn meter. Over multi-wave encounters, triggering the bonus every two to three turns grants additional full actions within strict cycle limits without requiring unattainable Speed substats.

Best Characters and Rotation Requirements

Characters who gain the most value from Eagle of Twilight Line have low Energy costs, energy-refunding abilities, or rotations dedicated to cycling Ultimates quickly:

Pela: The premier user of the set. Combining Eagle with an Energy Regeneration Rate Planar Rope, her innate Energy-refunding passive, and Light Cones such as Before the Tutorial Mission Starts or Resolution Shines As Pearls of Sweat enables reliable two- to three-turn Ultimate rotations. This rhythm provides continuous defense shredding while generating frequent stacks for Acheron.
Silver Wolf: Advances her turns to reapply single-target debuffs, sustain Weakness implants before fast elite enemies take actions, and generate Skill Points via Basic Attacks.
Sparkle: Utilizing the set's turn advance pulls Sparkle forward after her Ultimate, allowing her to advance the primary damage dealer more frequently than standard two-piece Speed setups permit.

Speed Breakpoints with Eagle of Twilight Line

Memory of Chaos typically requires 160.1 Speed to secure two actions in the opening cycle (Cycle 0). Eagle of Twilight Line significantly lowers this sheet stat requirement.

Relic Setup	Sheet Speed Target	Realized Combat Output	Practical Advantage
Standard 2-Piece Speed / Rainbow	160.1+ SPD	2 actions in Cycle 0	Reliable, but requires extensive Speed substat rolls
4-Piece Eagle (3-Turn Ultimate)	~154 SPD	Effective ~168–174 SPD pacing	Frees substats for Effect Hit Rate, HP%, and DEF%
4-Piece Eagle (2-Turn Ultimate on Pela)	~143 SPD	Functions above a 160+ Speed baseline	Consistent Basic Attack cycling and debuff uptime

Because the advance reduces necessary Speed rolls on relics, extra substat budget can be redirected toward Effect Hit Rate to guarantee debuffs land, or defensive stats (HP% and DEF%) to keep fragile supports alive.

Timing Rules and Execution Risks

The four-piece bonus requires specific activation timing to avoid losing value.

Avoiding Clipped Actions

Never activate a support's Ultimate while their Action Value is sitting at 0 (during their active turn). Triggering the Ultimate during the character's own turn applies the 25% advance when there is zero remaining meter to reduce, completely wasting the four-piece effect. Always fire the Ultimate immediately after the unit completes their Basic Attack or Skill, right as their action counter resets.

Managing Buffs and Skill Points

Because Eagle carriers cycle turns rapidly, they can lap slower allies. If a support acts too frequently, short-duration buffs applied to them by other teammates will expire faster. Additionally, verify that an accelerated support relies primarily on Basic Attacks; otherwise, extra turns may drain Skill Points needed by your primary damage dealer.

Farming and Synthesis Recommendations

Eagle of Twilight Line drops from the Cavern of Corrosion: Path of Gelid Wind in Cloudford on the Xianzhou Luofu. Because it shares drop rates with the Hunter of Glacial Forest Ice damage set, spending direct Trailblaze Power there can be inefficient unless you actively build Ice damage dealers like Jingliu or Yanqing.

To gear supports efficiently:

Farm higher-efficiency caverns (such as those offering Pioneer or Duke sets) for general account upgrades.
Salvage unwanted 5-star relics into Relic Remains at the Omni-Synthesizer.
Craft targeted Eagle of Twilight Line pieces, aiming for Speed boots via normal synthesis.
Save Self-Modeling Resin to craft 5-star Energy Regeneration Rate Planar Ropes, which are mandatory for maintaining the rapid Ultimate cycles this set requires.