Acheron — Honkai Star Rail Character Guide

Overview

Stack-based Nihility DPS who ignores weakness types and shreds All-Type RES during her Ultimate. Gains a massive separate DMG multiplier with Nihility teammates, freeing premium Harmony supports for other teams.

Stack-based Nihility DPS whose Ultimate replaces the standard Energy system with Slashed Dream points (9 to activate). Stacks are generated by Acheron's own Skill (+1) and whenever any ally inflicts a debuff on an enemy (+1). During her Ultimate, she unleashes 3 targeted Rainblades that consume Crimson Knot stacks for bonus AoE DMG, followed by a Stygian Resurge finisher hitting all enemies. The Talent provides 20% All-Type RES reduction and Toughness reduction regardless of Weakness Types during the entire Ultimate sequence.

Key Mechanics

• Requires 2 Nihility teammates (3 total including Acheron) at E0-E1 to activate the full 160% A4 separate DMG multiplier. Dropping to 1 Nihility teammate reduces the multiplier to 115% — a major damage loss. E2 reduces the requirement by 1.
• Slashed Dream generation rate determines Ultimate frequency. Each ally ability that inflicts a debuff grants 1 stack; Acheron's own Skill grants 1 stack. Signature LC adds a debuff per attack, doubling Skill generation to 2 stacks. Jiaoqiu uniquely generates stacks during enemy turns.
• Crimson Knot management is critical for Ultimate damage. Each of the 3 Rainblades should target an enemy with at least 3 Crimson Knot stacks to maximize the AoE DMG component. The Auto AI handles targeting correctly.
• Does not use the Energy system at all — Energy-related buffs and effects (Tingyun Energy restore, Energy Regeneration Rate) provide zero value. Only Slashed Dream generation matters.
• CRIT scaling is the dominant damage stat. Unlike Break or DoT characters, Acheron scales purely with ATK, CRIT Rate, CRIT DMG, and DMG%. The A4 separate multiplier and A6 DMG% stacking provide substantial self-buffing, reducing reliance on Harmony supports.

Best Teams for Acheron

Double Nihility Hypercarry

Standard Acheron composition with two Nihility debuffers. Maximizes the A4 trace bonus (160% separate DMG multiplier applied after all other calculations) while maintaining consistent Slashed Dream generation through ally debuffs. Because the A4 multiplier bypasses diminishing returns entirely, this is Acheron's highest damage ceiling at E0-E1. Works at all eidolon levels.

• S-tier: Acheron, Jiaoqiu, Cipher, Dan Heng • Permansor Terrae
• A-tier: Acheron, Cipher, Silver Wolf, Dan Heng • Permansor Terrae
• B-tier: Acheron, Pela, Silver Wolf, Aventurine
• A-tier: Acheron, Welt, Jiaoqiu, Pela
• A-tier: Acheron, Welt, Pela, Aventurine

Harmony Flex

E2-exclusive composition replacing the second Nihility slot with a Harmony support. E2 reduces A4 requirement from 2 Nihility to 1, preserving the full 160% separate DMG multiplier while enabling action advancers like Sunday or Sparkle to dramatically accelerate Slashed Dream generation through rapid Skill usage. Combined with E2's turn-start stack, Acheron can generate 3+ stacks per cycle and maintain extremely short Ultimate rotations.

• S-tier: Acheron, Cipher, Sunday, Dan Heng • Permansor Terrae
• A-tier: Acheron, Cipher, Tribbie, Aventurine

Best Teammates

Amplifiers: Jiaoqiu (S+), Cipher (S+), Pela (A), Silver Wolf (A), Welt (A), Tingyun • Fugue (B)

Sustains: Dan Heng • Permansor Terrae (S+), Aventurine (A), Fu Xuan (A), Hyacine (A), Gallagher (B)

Investment Priority

1. E1 — +18% CRIT Rate vs debuffed enemies — permanent uptime in optimal teams. Frees relic investment from CRIT Rate and lets you stack CRIT DMG instead. Strong recommended first target before signature.
2. LC S1 — Signature applies debuff on every attack, doubling Slashed Dream generation per Skill (2 stacks instead of 1) and providing a substantial Ultimate DMG boost. The fastest way to smooth out Acheron's rotation after E1.
3. E2 — Best spender stopping point. Reduces Nihility requirement from 2 to 1 for max A4 buff (160% separate DMG multiplier), opening the Harmony flex slot for Sunday/Sparkle/Tribbie. Also generates 1 Slashed Dream per turn start, accelerating Ultimate frequency by ~25%.

Best Relics

Recommended: pioneer-diver-of-dead-waters with izumo-gensei-and-takama-divine-realm

Stat targets: CRIT Rate 70%+, CRIT DMG 160%+, SPD 101 or 135+, ATK 3000-3500

Main stats: Body: CRIT Rate / CRIT DMG · Feet: SPD / ATK% · Sphere: Lightning DMG / ATK% · Rope: ATK%

Important Notes

• Requires 2 Nihility teammates at E0-E1 for max A4 multiplier (160%) — dropping to 1 Nihility cuts it to 115%, a major damage loss
• Without Jiaoqiu, stack generation slows significantly in modern endgame — he generates stacks during enemy turns that no other support replicates
• Signature LC provides largest consistent performance gap of any Nihility LC — doubles Skill stack generation rate
• Sustain choices should prioritize debuff access: Trend of the Universal Market on Aventurine/Fu Xuan, or natural debuffers like Gallagher and Hyacine with signature
• E0 base CRIT Rate is low — requires strong relics or E1 to reach the 70-80% CRIT Rate threshold needed for consistent damage