Phantylia the Undying Strategy

Master the Phantylia the Undying boss fight in Honkai: Star Rail with our comprehensive strategy guide. Learn weaknesses, phases, and optimal tactics for victory in 2026.

Stats / Weaknesses:

• Phantylia the Undying: Weak to Lightning, Wind, and Quantum.
• Adds (Wind/Lightning): Weak to Fire, Ice, and Imaginary.

Phases:

1. Phase 1: Phantylia summons two Wind/Lightning clones. Focus on defeating these adds quickly to prevent them from empowering Phantylia or launching devastating attacks. Break Phantylia's Toughness to interrupt her ultimate.
2. Phase 2: Phantylia unleashes more powerful attacks and summons more frequently. Continue to prioritize breaking her Toughness and managing adds. Use your ultimate abilities strategically to deal burst damage when Phantylia is vulnerable.
3. Phase 3: Phantylia becomes enraged, unleashing her full power. This phase is a race against time. Maintain aggressive offense while ensuring your team survives her onslaught.

Strategy:

• Bring characters with strong AoE capabilities to deal with the adds efficiently.
• Characters with debuffing abilities can be very useful in reducing Phantylia's damage output.
• Ensure your team has a good balance of damage dealers and support characters (healers/shielders).
• Prioritize breaking Phantylia's Toughness Bar whenever possible to interrupt her most dangerous attacks.
• Pay attention to the elemental weaknesses of the adds and Phantylia herself to maximize your damage.