Castorice Guide — Quantum Remembrance DPS (v3.4)

TL;DR

Castorice is a 5-star Quantum Remembrance DPS who summons a dragon companion named Pollux. She is a high-risk, high-reward character whose entire kit revolves around HP manipulation — draining her own and her allies' health to empower Pollux's devastating attacks. The more HP she drains over the course of battle, the harder she hits. She requires a dedicated healer to manage her team's health, but the payoff is some of the highest Quantum AoE damage in the game. Castorice is a premiere v3.4 DPS for MoC and endgame content.

Core Mechanics

Pollux — Dragon Companion (Memosprite)

Castorice's Skill summons Pollux, her dragon memosprite companion. Pollux has its own HP bar, action value, and turn order — it acts independently on its own turn. Pollux's Basic Attack deals Quantum damage to a single enemy, while its enhanced Skill drains HP from both Castorice and her teammates to fuel a powerful AoE breath attack. Pollux accumulates a Bond Meter as it attacks and as HP is drained; when the Bond Meter is full, Pollux uses its Ultimate ability — a massive AoE Quantum nuke that consumes all stored HP debt for bonus damage. Pollux remains on field until its HP reaches 0 or Castorice uses her own Ultimate.

HP Drain & Blood Debt

Castorice's Skill and Ultimate both cost a percentage of her current HP rather than Energy. Pollux's enhanced abilities also drain HP from the entire team. This drained HP accumulates as Blood Debt, a hidden resource that Castorice tracks. The more Blood Debt stored during battle, the higher the damage multipliers on Castorice's Ultimate and Pollux's Bond attack. At low HP thresholds (below 35%), Castorice gains significant damage bonuses and extended Pollux uptime. This creates a fascinating risk/reward dynamic where low health is actually optimal for damage output.

Healer Synergy

Because Castorice constantly drains her team's HP, she has an absolute requirement for a strong sustain unit. However, she also benefits from healing more than most DPS — certain supports trigger additional effects when healing a low-HP ally, and Castorice's own kit has passives that convert overhealing into temporary ATK buffs. Luocha is her premier healer due to his automatic field-healing, but abundance units with strong single-target heals also work well.

Best Light Cones

Best Relics & Planars

Stat Priority

• Body: CRIT Rate or CRIT DMG (aim for 1:2 ratio, prioritize CRIT Rate from Longevous)
• Boots: SPD (essential — Castorice and Pollux both benefit from faster turns)
• Orb: HP% (her damage scales with max HP, not ATK)
• Rope: HP% (more HP = more self-damage capacity = more Blood Debt = more damage)
• Substats: CRIT Rate / CRIT DMG > HP% > SPD (after 134 breakpoint)
• Target: 70%+ CRIT Rate, 150%+ CRIT DMG, 8000+ HP, 134+ SPD

Best Team Compositions

Premium HP-Synergy: Castorice + Sunday + Luocha + Ruan Mei

Castorice's strongest and most consistent team. Sunday provides energy regeneration and turn advance for both Castorice and Pollux — this is critical because faster Pollux turns mean faster Bond Meter generation. Luocha's auto-healing field is the perfect sustain for constant HP drain; he keeps the team at safe HP levels without consuming SP. Ruan Mei buffs team damage, extends Break duration, and provides RES PEN. This team has no downtime and maximizes Castorice's damage ceiling.

Hypercarry: Castorice + Bronya + Tingyun + Huohuo

Bronya advances Castorice for more frequent Skill uses and Pollux summons, while Tingyun provides ATK and Energy. Huohuo offers heals plus team Energy regeneration, which helps Castorice get her Ultimate back faster for refreshing Pollux. This team produces enormous single-target pressure and works well in boss-fight scenarios.

Dual Drain: Castorice + Jingliu + Luocha + Pela

An aggressive team that doubles down on HP-manipulation. Jingliu also drains ally HP (from her teammates' HP pool) to enter her enhanced state, creating a team-wide low-HP synergy. Luocha's healing output is stretched thin but still sufficient with proper gearing. Pela provides DEF shred that benefits both Quantum and Ice damage. This is a glass-cannon composition that clears waves extremely fast.

Budget: Castorice + Lynx + Tingyun + Pela

Accessible and functional. Lynx provides SP-positive healing with cleanse, which helps manage Castorice's HP drain. Tingyun boosts Castorice's energy, and Pela offers universal DEF shred. This team lacks the premium support damage amplification but can clear MoC floors comfortably with proper gearing.

Eidolons & Resonance

• E1: Pollux gains 20% Action Advance when taking damage. Much faster Bond generation.
• E2: Castorice's Blood Debt cap increases by 50%, allowing her to store more HP for bigger nukes.
• E4: Heals received by the team are converted to a stacking ATK buff. Excellent synergy with overhealing.
• E6: Pollux's Bond attack no longer costs team HP, and its base damage is doubled. Transformative power spike.

Rotation Tips

Opener: Castorice Skill → Summon Pollux → Pollux acts (Basic or Skill depending on enemy count). The goal is to drain HP as quickly as possible to build Blood Debt. Use Castorice's Ultimate when Pollux's Bond Meter is at least 80% full, because her Ultimate deals bonus damage proportional to Pollux's bond level. Keep Castorice below 50% HP if possible for her passive damage bonuses — but never let her fall so low that one enemy hit will kill her. Use Luocha's field or Huohuo's Ultimate proactively before Pollux's Bond attack to ensure the team survives the HP drain. In multi-wave content, pre-stack Blood Debt on the last enemy of a wave before finishing it off so you start the next wave with a loaded Bond Meter.

Frequently Asked Questions

Does Castorice need Energy?

Castorice does not use Energy for her Skill — it's HP-gated instead. However, her Ultimate still requires Energy to activate, so Energy Regeneration% from substats or supports like Tingyun/Huohuo is beneficial. Sunday's energy battery is particularly valuable for keeping both Castorice and Pollux operating at full capacity.

How much HP should Castorice have?

Aim for 8000+ total HP after gear. Her damage scales with max HP, every piece of her kit references HP percentages, and higher HP gives her a larger buffer for HP drain without requiring as frequent healing. HP% substats are roughly as valuable as CRIT substats for her total damage output.

Is Luocha mandatory for Castorice?

Not mandatory, but strongly recommended. Luocha's auto-field healing is uniquely suited to her playstyle because it fires without consuming SP and reacts to team-wide HP drain immediately. Huohuo, Gallagher, and Lynx are viable alternatives, but you will need to manage SP more carefully. Bailu works in a pinch for pure healing output.

Does Castorice work with Sunday?

Yes — Sunday is arguably Castorice's best support. His turn advance works on both Castorice and Pollux (since Pollux is a memosprite), his energy regeneration feeds her Ultimate, and his CRIT DMG buff is always welcome. Sunday + Castorice is one of the strongest DPS-support duos in v3.4.

What happens when Pollux dies?

If Pollux's HP reaches 0, it is banished from the field. Castorice must use her Skill again to resummon it, which costs an additional HP drain. This is a significant rotation loss, so keeping Pollux alive is important. Building HP on Castorice also increases Pollux's base HP. Luocha's emergency healing can save Pollux from death if timed well.

Is Castorice better than Seele at single-target?

In single-target scenarios, Seele still holds an advantage thanks to her Resurgence mechanic enabling extra turns and her higher single-target multipliers. However, Castorice significantly outperforms Seele in any multi-target scenario and against Quantum-weak enemies. For mixed content (2-3 enemies), Castorice is generally the stronger pick.