Kingdom Hearts (series)/Trivia

Seven and thirteen
The numbers seven and thirteen frequently reoccur throughout the Kingdom Hearts series. Seven is closely associated with light, while thirteen is associated with darkness.

Overarching

 * There are seven pure lights, the Princesses of Heart or New Seven Hearts.
 * There are seven protectors of light, the Seven Guardians of Light.
 * There are thirteen pure darknesses, the ancient entities known as.
 * The χ-blade shattered into seven pieces of light and thirteen pieces of darkness.
 * There are seven Lost Masters, The Master of Masters and his six apprentices.
 * There are thirteen main members of Organization XIII and the real Organization XIII.

Kingdom Hearts

 * The Keyhole in Neverland is located at the thirteen minute mark on Big Ben's clock face.
 * Sora can learn seven types of magic spells.
 * The Ars Arcanum attack consists of thirteen strikes.

Kingdom Hearts Chain of Memories

 * There are thirteen floors and thirteen basement levels in Castle Oblivion.
 * The Room of Beginnings in Castle Oblivion requires cards with the values 1 and 3.
 * The final Unknown Room in Castle Oblivion requires cards with a cumulative value of at least 13.

Kingdom Hearts II

 * Roxas spends seven days in the Simulated Twilight Town.
 * Roxas lands seven hits on DiZ's computer.
 * It takes thirteen hits to defeat Seifer in the first match.
 * Riku's Eternal Session Limit includes an ability named "XIII Blades".
 * Synthesizing the Ultima Weapon requires thirteen Orichalcum+.
 * There are a total of seven Orichalcum+ in the game, exactly the number needed after using an Energy Crystal.
 * The Fenrir Keblade has a strength increase of seven, the highest in the game.

Kingdom Hearts II Final Mix

 * Using the Restore Count Reaction Command against     restores the hit counter by thirteen points.
 * There are thirteen members of Mushroom XIII.
 * The Centurion staff has a strength increase of thirteen, the highest in the game.
 * The Winner's Proof Keyblade has a magic increase of seven, the highest in the game.

Kingdom Hearts Re:coded

 * There are a total of thirteen System Sectors.
 * The final System Sector has thirteen floors.
 * There are seven music tracks introduced in this game.

Kingdom Hearts 358/2 Days

 * The game begins on Day 7.
 * Roxas's first real mission with the Organization is Mission 7.
 * Luxord can wield a deck of Cards named Finest Fantasy 13.
 * There are thirteen music tracks introduced in this game.

Kingdom Hearts Birth by Sleep

 * There are thirteen matches in the Mirage Arena.
 * Vanitas is fought seven times across all three campaigns.

Kingdom Hearts Birth by Sleep Final Mix

 * The sum of the time on the Keyblade, 8:05, is equal to thirteen.
 * Once the Unknown fight is unlocked, the Land of Departure has a combat level of thirteen.

Kingdom Hearts 3D: Dream Drop Distance

 * Sora is "Combatant thirteen" when he faces Rinzler in The Grid.
 * As with the No Name, the sum of the time on Young Xehanort's Keyblade is equal to thirteen.
 * There are thirteen types of Training Toy candies.

Kingdom Hearts III

 * There are a total of seven Orichalculm+, all of which are required to synthesize the Ultima Weapon.
 * The box art, Gathering, shows thirteen main characters.
 * The clock tower in Gathering displays thirteen hours on the clock.

Kingdom Hearts III Re Mind

 * There are seven lights on the chandelier in the Garden of Assemblage.

Kingdom Hearts Dark Road

 * There are seven pupils in Xehanort's class.
 * There are seven upperclassmen who went missing.
 * Xehanort tells Eraqus that it would take thirteen lifetimes to rebuild the world.

Other

 * There are thirteen musical tracks whose titles contain the number thirteen.
 * There are thirteen letters in:
 * "Kingdom Hearts"
 * "Light" and "Darkness"
 * "End of the World"
 * "Hollow Bastion"
 * "Radiant Garden"
 * "Sora", "Riku", and "Kairi"
 * "Sora", "Roxas", and "Xion"
 * "Roxas", "Axel", and "Xion"
 * "Terra-Xehanort"
 * "Ventus-Vanitas"
 * The Director's Secret Report XIII is a thirteen-part exposé by Tetsuya Nomura.
 * As of the 10th anniversary of the series, there were seven main games.
 * As of the 20th anniversary of the series, there were thirteen main games.

Kingdom Hearts Magical Puzzle Clash

 * The orange token is unlocked upon reaching level seven.
 * The purple token is unlocked upon reaching level thirteen.

Kingdom Hearts Trading Card Game

 * A player wins the game if the value of their World Cards totals thirteen.