Acheron is set to gain a new upgrade option through the Ex-Eidolon system appearing in the Honkai: Star Rail version 4.7 beta. It adds an extra effect to her kit without requiring more copies of the character, and early test builds already pair it with heavy follow-up attack teams to push her damage well past her usual ceiling.
Quick answer: Acheron’s Ex-Eidolon, A Glance Through Rime to Bone, deals extra Lightning damage and launches a follow-up attack whenever an ally hits an enemy carrying a Crimson Knot. It is beta data and subject to change.
What the Ex-Eidolon system is
Ex-Eidolon is a new slot on the Eidolon page, placed after the existing E1 through E6 ranks. Instead of pulling duplicate copies of a five-star, you unlock it with a new material. Activating it grants the character an extra passive along with fresh UI, animations, and sound effects.
Three limited five-star characters are listed in the first batch of data: Acheron, Jing Yuan, and Dan Heng • Imbibitor Lunae. A tie-in activity lets you select one of the three to receive for free, in a format similar to past giveaway events. The other two Ex-Eidolons are tied to top-up or paid methods.
Everything about Ex-Eidolon comes from a test build. The slot, the unlock material, and the exact effect values have not appeared in a live version and can change before release.
Acheron’s Ex-Eidolon effect: A Glance Through Rime to Bone
Acheron builds toward her ultimate, Slashed Dream Cries in Red, by stacking Slashed Dream from debuffs and Crimson Knots applied to enemies. A Glance Through Rime to Bone hooks directly into that loop. When any ally strikes an enemy afflicted with a Crimson Knot, Acheron deals additional Lightning damage and performs a follow-up attack.
The practical result is more hits per turn and faster stack generation. Each extra follow-up feeds her ultimate charge and lets her cycle Slashed Dream Cries in Red more often, which is where the bulk of her true damage comes from.
The other two buffs
- Jing Yuan — One Quiet Cup of Thunder: increased damage dealt and additional Lightning-Lord hits when using Skill or Ultimate.
- Dan Heng • Imbibitor Lunae — Moonset Stills the Deep: a damage dealt increase, with the numerical values still pending in the beta.
What the beta footage shows about Acheron’s damage
Test footage runs Acheron in a follow-up attack lineup alongside a Fire-element Blade variant called Mortenax Blade, the Hunt Lightning character Ashveil, and the Harmony support Tribbie. Because the beta hands follow-up attacks to characters who normally lack them, nearly every teammate contributes to the Crimson Knot triggers that fuel Acheron.
In the Anomaly Arbitration-style encounter, the team clears an opening wave before reaching the two-phase boss Murata Graphia, Founding Artist. The boss locks its health with a Voracity mechanic that must be suppressed to finish it, and the follow-up chains let Acheron keep slashing through both phases.
The same team then clears a Pure Fiction stage in the Fictional Ensemble format, pushing to the full 40,000-point challenge goal across three waves that end with Furiae Praetor and the Flame Reaver of the Deepest Dark. The repeated follow-ups rack up score far faster than Acheron manages on her own.
The test team builds
The lineup leans on high action frequency and follow-up attacks. Three members run Eagle of Twilight Line for action advance, while Ashveil anchors the follow-up damage with the Ashblazing Grand Duke set.
| Character | Path | Light Cone | Relics |
|---|---|---|---|
| Acheron | Nihility | Along the Passing Shore | Eagle of Twilight Line (4) + Izumo Gensei and Takama Divine Realm (2) |
| Mortenax Blade | Nihility | Reforged in Hellfire | Use four Eagle of Twilight Line pieces with two pieces from Sprightly Vonwacq. |
| Ashveil | The Hunt | The Finale of a Lie | Pair four pieces from The Ashblazing Grand Duke with two from City of Converging Stars. |
| Tribbie | Harmony | Dance! Dance! | Use four Eagle of Twilight Line pieces with two pieces from Sprightly Vonwacq. |
Acheron’s card shows about 194% CRIT DMG with her signature cone, while Ashveil leans on her own high crit stats as the dedicated follow-up carry. These are beta configurations built around mechanics that may not ship as shown.
When it could arrive
Version 4.6, featuring Pearl, Evanescia, and Mortenax Blade, runs until November 10, with version 4.7 and the Aeon Aha content following after. Ex-Eidolon is reported for a future test build rather than being live in the current one, so no confirmed in-game date for the system has been set.
Until it reaches a public version, treat the follow-up attack buff, the unlock material, and the free-pick activity as beta data. The structure is clear enough to plan around, but the numbers and the final list of eligible characters can still shift before launch.
