C4 Tankfei Guide: Best F2P Shield for Mavuika 2026

Understanding Tankfei: The C4 Shield Transformation

Yanfei's C4 Done Deal fundamentally changes her from DPS to shielder. Her Burst generates a shield equal to 45% Max HP lasting 15s with 250% Pyro absorption.

At level 90, base HP is 9,352. Tankfei builds push total HP to ~40,000 through HP% artifacts and weapons, creating ~18,000 absorption shields—comparable to invested Thoma (14,357) and approaching Zhongli (13,342).

For Genesis Crystals to reach C4, Genshin Impact Recharge Online through BitTopup provides secure purchases.

C4 vs Standard Builds

Standard Yanfei prioritizes ATK%, Pyro DMG (24.0% ascension stat), and CRIT. Tankfei uses HP% on Sands/Goblet/Circlet, increasing shield absorption from 9,049 to 19,528 at level 90 talent 9.

C4 is mandatory—C0-C3 can't generate shields. C1 (stamina reduction) and C6 (+1 Scarlet Seal) offer marginal shielder benefits.

Shield Mechanics

Burst costs 80 Energy, 20s cooldown, 15s duration. Shield activates instantly—no stacking required like Thoma. Against Pyro attacks, 250% absorption creates 45,000 effective HP.

Why Mavuika Needs Shields

Mavuika C0 has zero interruption resistance. Level 90 stats: 12,552 HP, 359 ATK, 792 DEF, 88.40% CRIT DMG—pure offense. Shields apply 0.0 poise damage multiplier, preventing staggers during her extended attack sequences.

Lantern Rite 2026 Selector Strategy

Version 6.3 launches January 14, 2026. Event requires AR20 + Archon Quest Prologue Act III.

Available: Beidou, Chongyun, Gaming, Lan Yan, Ningguang, Xiangling, Xingqiu, Xinyan, Yanfei, Yaoyao, Yun Jin.

Yanfei is the only character whose constellation creates an entirely new role.

Evaluating Your Roster

Check current Yanfei constellation. At C3, this selector completes Tankfei immediately. At C0-C2, consider if you can get copies from standard banner before February 23.

For Mavuika owners lacking Zhongli/Layla/invested Thoma, Tankfei fills a critical gap in F2P Vaporize (Mavuika/Xingqiu/Xiangling/Bennett) or Melt teams.

Why C4 Yanfei Outvalues Others

Xingqiu/Xiangling are top-tier but most veterans have high constellations already. Yaoyao heals but lacks shield strength. Gaming offers damage, no defense. Xinyan's shields scale poorly.

Tankfei uniquely combines shielding + Pyro Resonance (25% ATK) + potential Prototype Amber healing in one slot.

Investment Returns

Ascension to 90: 168 Noctilucous Jade, 46 Juvenile Jade, 420,000 Mora. Talents 8/8/8: 9 Teachings, 63 Guides, 114 Philosophies of Gold (Taishan Mansion Tue/Fri/Sun).

Burst priority. Level 10 requires 1 Crown, 6 Bloodjade Branch, 3/21/38 Gold books. Each level increases shield absorption directly.

Mavuika Synergy

Mavuika's 15s damage windows align perfectly with Tankfei's 15s shield duration. 20s cooldown matches rotation lengths. Instant shield application eliminates gap vulnerability.

Pyro Resonance Benefits

25% ATK boost for all members. Unlike Cryo shielders (Layla/Diona), Tankfei maintains clean Pyro Resonance with comparable shield strength.

In Vaporize teams, double Pyro ensures consistent application. In Melt teams, brief Pyro doesn't disrupt Cryo aura.

Energy Generation

80 Energy Burst appears demanding, but 240% ER achieves ~75% uptime. Prototype Amber (41.3% HP at 90) generates 12 Energy post-Burst (4 particles × 3 ticks), reducing ER requirements.

Complete Build Guide

Artifact Sets

4pc Noblesse Oblige: 20% ATK boost for 12s after Burst—stacks with Pyro Resonance for 45% total. Default recommendation.

2pc Tenacity + 2pc Emblem: 20% HP + 20% ER. For players struggling with ER requirements.

4pc Instructor: 120 EM after reactions—inferior to Noblesse for Mavuika teams.

Main Stats

• Sands: ER or HP%
• Goblet: HP%
• Circlet: HP%

ER Sands if you can't reach 240% ER through substats/weapon. HP Sands provides more shield but requires Prototype Amber energy or exceptional ER substats.

Weapons

Prototype Amber R1 (level 90): 41.3% HP, heals 4.5% Max HP/s for 6s (27% total). At 40,000 HP = 10,800 healing. 12 Energy generation significantly reduces ER needs.

Thrilling Tales R5: 48% ATK buff for 10s but sacrifices healing/energy. Requires immediate swap to Mavuika.

Substats

1. ER to 240% (HP Sands) or 200% (ER Sands)
2. HP% to maximize absorption
3. Flat HP secondary
4. All else irrelevant

Don't chase perfect HP substats. 35,000 HP + 240% ER > 45,000 HP + 180% ER.

Shield Calculations

Formula: Shield Absorption = Max HP × 0.45

• 40,000 HP = 18,000 absorption
• 35,000 HP = 15,750 absorption
• 30,000 HP = 13,500 absorption

HP Thresholds

• Minimum: 30,000 HP (13,500 absorption) - overworld/early Abyss
• Recommended: 35,000 HP (15,750 absorption) - Floor 12 with dodging
• Optimal: 40,000 HP (18,000 absorption) - face-tank most attacks

Talent Priority

Burst > Skill > Normal Attack

Burst to 8 minimum, 9-10 if resources allow. Skill to 6-8 for particles. Normal Attack stays at 1—never used.

Shielder Comparison

vs Thoma

Thoma: 14,357 absorption when fully stacked, requires 2-3s + Normal Attacks to reach max. Tankfei: instant full-strength, no maintenance.

Both provide Pyro Resonance, but Tankfei adds Prototype Amber healing. Thoma's C6 (15% NA/CA/Plunge bonus) irrelevant for Burst-focused Mavuika.

vs Layla

Layla has stronger shields but eliminates Pyro Resonance (25% ATK loss). In Melt teams, her Cryo can disrupt Mavuika's triggers. Better for Freeze/Physical teams.

vs Xinyan

Xinyan's DEF-scaling shields reach only 8,000-10,000—insufficient for Floor 12. Physical DMG bonus useless for Pyro Mavuika. Failed hybrid design.

vs Zhongli

Zhongli: 13,342 absorption, 20s duration, 12s cooldown, universal shred. Strongest shielder but requires 180 pulls average.

Tankfei provides 80-90% defensive value at zero primogem cost. Zhongli's comfort is undeniable, but Tankfei's accessibility wins for F2P.

Buy Genesis Crystals through BitTopup for secure purchases with instant delivery.

Rotations & Teams

Standard Rotation

Team: Mavuika, Tankfei, Xingqiu, Bennett

1. Bennett Burst (4s) - ATK buff + healing
2. Xingqiu Skill + Burst (6s) - Hydro application
3. Tankfei Burst (2s) - Shield + Noblesse buff
4. Mavuika Skill + Burst (15s) - Full damage rotation
5. Repeat (20s cycle)

Mavuika receives Bennett ATK, Noblesse ATK, Pyro Resonance, and shield simultaneously.

ER Breakpoints

At 240% ER with Prototype Amber, Tankfei generates ~60 Energy/rotation:

• Prototype Amber: 12
• Bennett particles (funneled): 15-18
• Xingqiu particles: 8-10
• Natural regen: 10-12
• Tankfei Skill: 12-15
• Total: 57-67 Energy

Gap closes through catching Bennett particles during Tankfei field time and using Skill before swapping.

200% ER = 60% uptime (dangerous gaps). 260% ER = 85-90% uptime (excessive investment).

Team Options

Core: Mavuika + Tankfei

Vaporize Flex: Xingqiu (Hydro + damage reduction), Yelan (stronger Hydro + DMG bonus), Mona (Omen + TTDS)

Support Flex: Bennett (ATK + healing + battery), Kazuha (Elemental DMG + VV), Sucrose (EM + VV + TTDS)

Budget F2P: Mavuika, Tankfei, Xingqiu, Bennett—zero 5-stars beyond Mavuika.

Animation Cancel

Burst animation = 2s. Dash-cancel after shield appears reduces to 1.2-1.5s. Practice: Burst → shield appears → dash → swap.

Common Mistakes

Building Hybrid Damage/HP

Commit fully to HP/ER. 40,000 HP + zero damage > 25,000 HP + mediocre CRIT. Her role is enabling Mavuika, not personal damage.

Energy Management Errors

Funnel particles to Tankfei during field time. When Bennett uses Skill, keep Tankfei on-field. Always use Skill → Burst unless at 80+ Energy.

Talent Priority Mistakes

Burst first to 8 minimum. Skill to 6. Normal Attack stays at 1. Don't level all talents equally—wastes resources.

Constellation Roadmap

• C0: No shielder capability - 0/10
• C1: Stamina reduction - 1/10 (irrelevant)
• C2: CRIT Rate buff - 0/10 (no damage focus)
• C3: +3 Skill levels - 2/10 (minor particles)
• C4: Shield unlock - 10/10 (MANDATORY)
• C5: +3 Burst levels - 3/10 (doesn't affect shield)
• C6: +1 Scarlet Seal - 1/10 (irrelevant)

Stop at C4 unless building secondary DPS.

Material Priority

Week 1-2: Noctilucous Jade + Juvenile Jade. Prioritize level 80 ascension before 90.

Week 3-4: Gold books (Taishan Mansion). Burst to 8, Skill to 6.

Week 5+: Artifacts. Noblesse domain (Clear Pool). HP% main stats first, optimize substats later.

Resin Cost

• Ascension: ~800 Resin (4 days)
• Talents 8/6/1: ~1,200 Resin (6 days)
• Artifacts: ~1,500-2,500 Resin (7-12 days, RNG)
• Total: ~3,500-4,500 Resin (17-22 days)

Advanced Strategies

Spiral Abyss Floor 12

Floor 12 attacks deal 3,000-8,000 damage/hit. 18,000 shields withstand 2-6 hits—sufficient with dodging. Against Pyro chambers, 250% absorption = 45,000 effective HP (essentially unbreakable).

Multi-target chambers benefit from instant full-strength shields vs Thoma's stacking requirement.

Enemy Attack Patterns

High-frequency low-damage (Ruin enemies): Shields excel, absorb dozens of hits.

Low-frequency high-damage (Ruin Serpent, Maguu Kenki): Dodge telegraphed attacks even with shields. 15,000 damage hits break shields.

DoT effects (Corrosion): Prototype Amber healing counters gradual drain.

Stamina Management

Avoid unnecessary Charged Attacks. Use Skill → Burst → Swap without filler. Save stamina for emergency dodges.

Resource Acquisition

Farming Routes

Noctilucous Jade: Mingyun Village, Cuijue Slope, Tianqiu Valley. 50+ spawn locations, 48hr respawn.

Juvenile Jade: Primo Geovishaps (40 Resin, 2-3 drops) or free Geovishaps (Tianqiu Valley, Cuijue Slope).

Gold Books: Taishan Mansion (Tue/Fri/Sun). Use Condensed Resin.

Prototype Amber: Forge with 1 Northlander Catalyst Billet (weekly bosses, Abyss, Souvenir Shops).

Lantern Rite Rewards

Complete all stages for primogems, talent books, materials. Event runs 24 days—spread activities to avoid burnout.

FAQ

What does C4 Yanfei do? Generates shield = 45% Max HP on Burst, 15s duration, 250% Pyro absorption. At 40,000 HP = 18,000 absorption.

Tankfei vs Thoma for Mavuika? Tankfei wins. Instant full-strength shields, no Normal Attack stacking, Prototype Amber healing, identical Pyro Resonance.

How much HP needed? 35,000-40,000 HP for endgame. 35,000 = 15,750 absorption (Floor 12 with dodging). 40,000 = 18,000 (face-tank most attacks).

Which Lantern Rite character to pick? For Mavuika owners lacking shielders: C4 Yanfei (or progress toward C4). Otherwise: Xingqiu/Xiangling constellations if not C6.

Best artifacts? 4pc Noblesse (20% ATK buff). Alternative: 2pc Tenacity + 2pc Emblem. Main stats: ER or HP% Sands, HP% Goblet, HP% Circlet. Reach 240% ER first.

How often can Tankfei shield? At 240% ER + Prototype Amber: ~75% uptime on 20s cooldown. Shields every 20-23s in optimal rotations—covers Mavuika's damage windows.

Ready for C4 Yanfei this Lantern Rite? BitTopup offers instant Genesis Crystal delivery with secure payments and competitive pricing. Build your Tankfei and dominate endgame with reliable shields and Pyro Resonance!