Persona 5 The Phantom X First Boss Battle Strategy

Persona 5 The Phantom X’s first main Palace boss is Shadow Kiuchi (Cupid), the “Subway Slammer.” Beating him is about surviving his big physical hits, abusing Fire/Elec weaknesses (and later Nuclear), and killing his minions quickly in phase two.​

Recommended Level, Team, and Prep

• Aim for roughly the game’s suggested level for Kiuchi’s Palace boss (low–mid 30s on most servers); if the fight feels impossible, level and upgrade weapons a bit more first.​
• Bring:
  • Wonder with Fire and Electric (or Nuclear) Personas.
  • A Fire DPS (Panther, Cattle) or Elec DPS (Closer) for extra weakness hits.
  • One strong healer (Cattle, Marian, Morgana-type) and, if possible, an Elucidator/Shield support like Puppet.​
• Stock some HP and SP items from Shibuya shops or eat food before the fight to get passive regen each turn.​

This setup ensures you can exploit Kiuchi’s minion weaknesses and stay alive through his big attacks.

Phase 1 – Human Form (Warm-Up)

Phase 1 is straightforward chip damage while learning his patterns.​

• Shadow Kiuchi’s human phase:
  • Resists Gun, nulls Wind, and has no other major weaknesses.​
  • Uses single-target Physical attacks like Hypersonic Slider and Triple Hit Streak; at half HP he starts taking two actions per turn.​
• Strategy:
  • Keep HP topped up and guard with low-HP characters if you expect to be focused.
  • Use Defense buffs and Attack debuffs if available to soften his physical pressure.
  • Focus on safe, consistent damage with Wonder and your main DPS, this phase is about not burning all your resources early.​

Once you deplete his first health bar, the real fight begins.

Phase 2 – Minions, Big AoE, and Weakness Abuse

At the start of Phase 2, Kiuchi transforms and calls in two minions (Devoted Girl and Delusional Girl), then blasts the party.​

• Opening of Phase 2:
  • Kiuchi uses a strong AoE attack (Fanatic’s Fastball-type) that hits the entire team once, so enter the phase with high HP and be ready to heal immediately.​
  • Two minions appear:
    • Devoted Girl – weak to Fire and Nuclear.
    • Delusional Girl – weak to Electric and Nuclear.​
• Priority:
  • Immediately target and kill both minions before Kiuchi’s next big AoE; if they survive, he can repeat the devastating team-wide attack at higher power.​
  • Use Fire on Devoted Girl and Elec on Delusional Girl (or Nuclear on both) to trigger One Mores and wipe them quickly.​

While the minions are alive, Kiuchi receives periodic healing, so removing them is essential to stop his sustain and unlock a damage window.​

Punish Windows and Defending Big Hits

Killing both minions temporarily disables Kiuchi and opens him up.​

• After both girls are defeated:
  • Kiuchi is stunned for 1 turn and takes roughly 20% more damage from all sources.​
  • This is your main burst window, dump your strongest skills, buffs, and debuffs here.
• Ongoing pattern:
  • Each turn, Kiuchi marks a target at the end of his turn; that character will be hit next with a huge single-target move (Lustful Drive Ball).​
  • Have the marked target Guard, top their HP, and apply a shield if your support allows it (Puppet-style Elucidators are great here).​

Kiuchi then alternates between resummoning minions and using big attacks. Repeat the rotation: kill minions fast with weaknesses → burst Kiuchi during his stunned window → defend the marked target.​​

Universal First-Boss Tips

• Don’t be afraid to leave and come back: you can always improve weapons, Personas, and reveal sets before sending the Calling Card, once you send it, the boss fight begins.​
• Maximize elemental coverage and manage SP: bring enough elements to cover minion weaknesses and keep at least one strong heal online for long fights.​
• Use buffs and debuffs: Attack/Defense buffs, Defense Down on Kiuchi, and Attack Down on him all make the second phase much safer.​

Following this pattern, prepping your team, sniping the minions with Fire/Elec/Nuclear, guarding Kiuchi’s marked target, and bursting him during stun, turns the first Palace boss from a wall into a manageable, well-paced fight.