Storyline: The universe of Kingdom Hearts is a collection of various levels, referred to as "worlds", through which the player must progress. Thirteen can be accessed in the game and one, Disney Castle, is shown in cutscenes. Additional worlds are mentioned by various characters but are inaccessible because they have been destroyed by the Heartless. Ten Disney worlds are based on fiction, primarily from the Disney animated features canon, and the other four were created by Square specifically for the game. The graphics and characters of each world were designed to resemble the artwork style of each Disney film. Each Disney world is inhabited by characters from the film: including Hercules and Philoctetes in Olympus Coliseum, and Aladdin, Princess Jasmine and Jafar in Agrabah. Each world is disconnected from the others and exists separately. Most characters in the world are unaware of other ones, with few exceptions. Players travel from one world to another via Gummi Ship. The worlds created specifically for the game mirror the overall appearance of the other worlds and feature either new characters or ones from several Final Fantasy games. The new worlds include: the Destiny Islands, where the story opens; Traverse Town, which serves as a launching point for most of the game; Hollow Bastion, which many of the Final Fantasy characters call home; and the End of the World, a large, dark world created from the remnants of various worlds consumed by the Heartless. The main characters travel from world to world to seal each "Keyhole"; this protects the world from the Heartless and ultimately from destruction. They also try to minimize their interaction with characters of other worlds to maintain a balance of separation. This sometimes requires Sora, Donald and Goofy to blend in with the world inhabitants by changing their physical appearance. Kingdom Hearts begins with Sora's Dive to the Heart, which foreshadows the events that will soon take place, but soon progresses to Destiny Islands, where Sora lives with his two best friends, Riku and Kairi. The three friends seek to leave the islands to explore new worlds and have prepared a raft for this purpose. One night, the islands are attacked by darkness and shadow creatures. Sora seeks out his friends, finding Riku first; Riku disappears into darkness, curious about what it contains. Soon after, Sora obtains a mysterious weapon, the Keyblade, to defend himself. Using it to fend off the creatures, he heads for a secret cave, where he finds Kairi near a door. She turns to him, saying his name as the door behind her blows open. The ensuing blast of darkness sends Sora and Kairi both out of the cave. The islands are soon destroyed, and Sora is left adrift, Riku and Kairi's whereabouts unknown.