Castorice — Honkai Star Rail Character Guide

Overview

HP-scaling Quantum DPS who charges Ultimate via team HP drain to summon Netherwing, a memosprite that applies 20% All-Type RES PEN and deals devastating AoE burst. Completely SP neutral, but requires direct healers — shields break her kit entirely.

HP-scaling Quantum DPS who drains all allies' HP via Skill to charge Newbud, a unique resource replacing Energy. When Newbud reaches 100%, summons the memosprite Netherwing for devastating AoE burst damage. All ability multipliers scale with Castorice's Max HP. Completely SP neutral (Skill costs 0 SP). Demands direct Abundance healers — shields intercept HP drain and break the entire kit.

Key Mechanics

• All damage scales with Max HP — ATK is completely useless. HP% is the primary stat, CRIT Rate and CRIT DMG are secondary offensive stats. DMG% has diminishing returns due to Talent stacking (60%) and Netherwing summoning bonus (10%).
• Requires direct Abundance healers (Hyacine, Luocha, Gallagher). Shields intercept HP drain before it generates Newbud, completely breaking the kit. A2 Trace converts healing into Newbud/Netherwing HP, making high-throughput healers essential for rotation speed.
• Netherwing acts as damage redirection — allies cannot drop below 1 HP while Netherwing is on field. Excess damage redirects to Netherwing at 500% of original value, rapidly draining its HP pool.
• Castorice's unique global passive "Mooncocoon" prevents ally death once per battle — allies receive a killing blow stasis that delays downing until they act, and is removed if healed or shielded before their next turn. Active even when Castorice is not in the current party.
• Poet of Mourning Collapse 4pc is near-mandatory: provides 32% CRIT Rate to both Castorice and Netherwing at below 95 SPD. A4 Trace's 40% in-combat SPD boost does not interfere with the pre-battle SPD check.

Best Teams for Castorice

Dual DPS

Dual DPS composition with Castorice and a secondary damage dealer paired with an amplifier and Hyacine. Two primary paths: Evernight (premium) provides 100+ CRIT DMG to Netherwing plus 30% Vulnerability and continuous Newbud generation, working with flexible amplifiers (Cyrene/RMC/Tribbie/Ruan Mei) for layered multiplicative buffs; or Mydei/Blade (alternative) creates mutual HP drain synergy where Castorice's drain accelerates partner mechanics while partner HP consumption generates Newbud, requiring stat-agnostic amplifiers like Tribbie. Hyacine's healing throughput converts directly to Newbud via A2 Trace and buffs Max HP for all members. Creates dual offense where both damage dealers are simultaneously amplified.

• S-tier: Castorice, March 7th • Evernight, Cyrene, Hyacine
• S-tier: Castorice, March 7th • Evernight, Trailblazer • Remembrance, Hyacine
• S-tier: Castorice, Trailblazer • Remembrance, Cyrene, Hyacine
• S-tier: Castorice, March 7th • Evernight, Tribbie, Hyacine
• A-tier: Castorice, Trailblazer • Remembrance, Ruan Mei, Hyacine
• A-tier: Castorice, Mydei, Tribbie, Hyacine
• B-tier: Castorice, Blade, Tribbie, Hyacine

Dual Amplifier

Two amplifiers and no sub-DPS focus all buffs exclusively on Castorice and Netherwing. Best when enemy target count is low and Netherwing's single-target burst ceiling outweighs Evernight's consistent AoE contribution. Cyrene Newbud overcap combined with a second amplifier (Tribbie for universal buffs, RMC for True DMG, Ruan Mei for Break/RES) creates stacking multiplicative layers that push Castorice's burst to its absolute ceiling. Higher damage ceiling than sub-DPS compositions in single-target scenarios at sufficient investment.

• S-tier: Castorice, Cyrene, Tribbie, Hyacine
• S-tier: Castorice, Trailblazer • Remembrance, Tribbie, Hyacine
• A-tier: Castorice, Cyrene, Trailblazer • Remembrance, Hyacine

Best Teammates

DPS Partners: March 7th • Evernight (S+), Mydei (A)

Amplifiers: Tribbie (S), Trailblazer • Remembrance (S), Cyrene (S+), Ruan Mei (A), Sunday (B), Cipher (B), Pela (C)

Sustains: Hyacine (S+), Luocha (A), Gallagher (A)

Investment Priority

1. LC S1 — Signature provides 30% DEF Ignore for Castorice and Netherwing plus 30% Max HP increase, which scales all skill multipliers. Action advance on Netherwing exit helps reach speed breakpoints. Best first investment due to limited Remembrance LC options.
2. E2 — Transformative — allows 6 consecutive Breath attacks instead of 4 and eliminates rotation downtime by advancing Castorice action by 100% after summoning Netherwing. Also provides 30% Newbud head start toward next summon. Recommended stopping point for spenders.
3. E1 — On the way to E2, provides consistent 20-40% DMG boost once enemies drop below 80%/50% HP. Worth noting as a milestone but not a standalone stopping point.

Best Relics

Recommended: poet-of-mourning-collapse with bone-collections-serene-demesne

Stat targets: HP% 7000+, CRIT Rate ~100% in-combat, CRIT DMG 200%+

Main stats: Body: CRIT DMG · Feet: HP% · Sphere: HP% / Quantum DMG · Rope: HP%

Important Notes

• Requires direct Abundance healers (Hyacine, Luocha, Gallagher) — any shield-based sustain completely breaks Newbud generation and renders her kit non-functional.
• Poor F2P Light Cone options — signature or high base HP cones (1270+) strongly recommended. Gap between signature and alternatives is larger than most 5-star characters.
• Team must sustain through 30-40% HP drain every Skill use — high healing throughput is mandatory, not optional. Castorice is extremely demanding on sustain units.