Build Your Deck and Reclaim the Lost Constellations

The stars above the Six Academies are going dark, one by one. The names and memories bound to them are vanishing as well.

Choose your Academy, build a 30-card deck, pursue sealed records, and recover scattered memories as you uncover the truth behind the fading stars.

Build a Strategy of Your Own

Choose minions, spells, and weapons from 168 cards available at launch. Create chains of effects around Academy skills, card abilities, and Bonds.

Manage your Mana, board position, and attack timing. Every turn asks you to choose between pressing the attack, protecting a key unit, or preparing for the next round.

Refine decks built around aggression, control, healing, Armor, spell combinations, sacrifice, or Fatigue, then test them against different enemies and Boss mechanics.

Master the Six Academies

Command the Ember, Tide, Gale, Stone, Radiant, and Umbral Academies.

Every Academy features a distinct hero skill, card synergies, and deck-building identity. Master a favorite strategy or expand your collection to explore new Academies and combinations.

Reshape Cards with Startraces

Fuse duplicate cards into a chosen main card and engrave it with permanent Startraces.

Combine Startraces, Bonds, Card Fates, and Boss Imprints to strengthen a card's attributes and tactical abilities. Even an ordinary card can grow throughout your journey and become the heart of your deck.

Challenge the Stolen Memories

Journey through an eight-chapter campaign spanning 60 nodes and confront eight Bosses with unique mechanics and changing phases.

Travel deeper into the Six Academies through card duels, story events, and route choices. Recover sealed records and piece together the memories scattered across the stars.

Each chapter features its own story sequence and Boss encounter. Study the Boss, adjust your deck, and prepare for each phase transition as you pursue the truth behind the Tide of Oblivion.

Raid Supercharged Bosses Together

Enter Co-op Raid with an AI companion or one friend. Each fighter brings their own 30-card deck to face eight supercharged Bosses.

Both players manage their own Health, hand, Mana, and board, taking turns before the Boss phase begins. Watch whether your teammate summoned, cast a spell, attacked, or used an Academy skill, then answer with the right action to trigger a team combo.

Some cards also gain co-op support abilities, allowing you to heal your teammate, grant Armor, and help the party survive the Boss's assaults.

Defeat seven rotating regular Bosses to unlock the final raid target. Clearing the finale opens a new raid cycle with a new rotation.

Conquer Extreme Bosses

Defeat a Co-op Boss on Normal to unlock its Extreme challenge.

Extreme Bosses have more Health, stronger phase mechanics, a faster tempo, and far more dangerous party-wide assaults. Victory demands more than a powerful individual deck—it requires complementary builds and carefully coordinated actions.

Clear an Extreme raid to earn bonus resources and a Boss Trophy Pack for your next challenge.

Choose Your Challenge

Beyond the complete Star Map campaign, several standalone modes await:

• Roguelike Adventure: Climb through eight floors of randomized trials. Choose routes across three difficulty levels, gain temporary upgrades, and push deeper into each run.
  
• Free Battle: Choose any available Academy and deck, then challenge the AI in a standalone duel.
  
• Eight Sovereigns: Unlocks after completing the main campaign. Use the same deck to face all eight Bosses in succession while Health carries between battles. Choose one field supply after every victory, with the Boss order changing between runs.
  
• Astral Arena: Unlocks after Chapter 1. Pursue seven wins before suffering three losses, face increasingly powerful opponents, and open a rank chest based on your final record.
  
• Co-op Raid: Fight supercharged Bosses alongside an AI companion or a friend, using support effects and team combos to complete repeated raid cycles.

Play Together Through Steam or LAN

The full Steam edition supports Steam friend rooms and invitations.

The full game also supports LAN duels and Boss raids. Create a room on the same local network and the game will automatically discover available sessions.

Whether you connect through Steam or LAN, both players can bring their own 30-card decks and face each other in a private one-on-one duel, or form a two-player party and challenge a Boss on Normal or Extreme. No public matchmaking server is required, making it suitable for homes, dorms, and in-person gatherings.

Play at Your Own Pace

Phantom Cardia: Astral Card Duel is a deck-building card game centered on offline single-player content, with additional AI co-op, LAN multiplayer, and Steam friend multiplayer.

The complete campaign, deck progression, and main challenges can be played offline. Even without going online, you can experience the full Co-op Raid rules with an AI companion.

The game is sold as a one-time purchase. Card packs and resources are earned through play, with no forced advertising, paid card pulls, or daily-task pressure.