Kingdom Hearts x Kamen Rider Den-O: Birth by Sleep

Kingdom Hearts x Kamen Rider Den-O: Birth by Sleep is a role-playing video game developed by Square Enix for the PlayStation Portable. It is an installment in the Kingdom Hearts series that focuses on Terra, Ven, and Aqua, characters introduced in Kingdom Hearts II Final Mix, and Kamen Rider Den-O. The game was announced at the 2007 Tokyo Game Show.

Plot
Long before Sora took up the keyblade, 10 years before the first Kingdom Hearts there were other keyblade masters and apprentices that existed. One day, one of these masters and his apprentice disappeared, foreshadowing a disaster to come. Another master, sensing the impending danger, sent three apprentices to find Master Xehanort and his cohort (the 'Dark Soldier' dubbed by fans). Kamen Rider Den-O appears to help out. Maleficent has been suspected as the main antagonist in this game, causing the disappearance of Master Xehanort and his apprentice, thus causing this 'great disaster' which was mentioned by Aurora in Kingdom Hearts. Many mysteries and any unexplained ideas about the keyblade will be answered and many connections to the main characters we know today will also be answered as well.

Characters

 * Terra
 * Ven
 * Aqua
 * Sora (Young)
 * Riku (Young)
 * Yen Sid
 * King Mickey
 * Donald
 * Goofy
 * Snow White
 * Cinderella
 * Jaq
 * Aurora
 * Hercules (Young)
 * Ben Tennyson
 * Gwen Tennyson
 * Kevin Levin
 * Master Xehanort
 * Master Xehanort's Apprentice
 * Unbirths
 * Maleficent
 * Wheel Master
 * Lucifer
 * Magic Mirror

Worlds

 * Den-Linear
 * Snow White's House
 * Castle of Dreams
 * Enchanted Dominion
 * Olympus Coliseum
 * Destiny Islands
 * Hollow Bastion/Radiant Garden
 * Sunset Horizons
 * Twilight Town (Yen Sid's Tower)
 * Bellwood

Gameplay
Birth by Sleep is a single player action role-playing game which features melee combat. The game is believed to have a gameplay similar to the style of the previous games in the series, particularly to Kingdom Hearts Re:Chain of Memories in that card decks will be used. Game director Tetsuya Nomura has mentioned players will play one world with 3 characters in different orders. As for gameplay, it will use decks, but not in the same way CoM did. BBS' battle system is much closer to KHII's than it is to CoM's.

Development
Birth by Sleep was announced alongside Kingdom Hearts 358/2 Days and Kingdom Hearts coded at the Tokyo Game Show on September 20, 2007. A trailer was shown in the Square Enix "Closed Mega Theater", a photo-prohibited theater presenting 40 minutes of trailers.

The game is being directed by Tetsuya Nomura, co-directed by Tai Yasue, produced by Patrick Chen, co-produced by Yoichi Yoshimoto and executive produced by Shinji Hashimoto. Birth by Sleep will use the same graphical engine as Final Fantasy VII: Crisis Core. The development of the game began before the release of Kingdom Hearts II Final Mix. Though the plot was completed, development was halted due to development of Re:Chain of Memories. Of the three new games announced, Birth by Sleep was the first one to begin development, though Nomura speculates it will be the last one released.