Digimon Frontier

Digimon Frontier (デジモンフロンティア), known as "Digimon 4" in South America, is the fourth Digimon TV series, first broadcast in 2002. After prompted to do so by unusual phone messages, five children go to a subway station and take a train to the. There, they meet and, who act as their guides and tell the children that the Digital World is being destroyed, and the children must fight the evil  and his Legendary Warrior servants in order to save the world.

Plot summary
The goal of the DigiDestined is to save the world, and to achieve that goal, they are granted the power to "Spirit Evolve" into the Legendary Warriors. For this special kind of evolution, they use Spirits, artifacts created by the that were hidden in certain areas of the. When the characters first arrive in the Digital World, their cell phones turn into digivices called D-Tectors. Each character actually acquires two Spirits each, the "Human Spirits" and the stronger "Beast Spirits", each with varying strengths and weaknesses. The DigiDestined mainly travel the world via railroads, where train Digimon called "Trailmon" act as a means of transport.

When the five DigiDestined arrive in the Digital World, they find themselves hunted by five other Legendary Warriors who serve the evil. After they defeat four of the enemy, Koji discovers that, the fifth evil Legendary Warrior, is really his estranged brother Koichi. With Takuya's help, Koji is able to free his brother, and Koichi restores the Spirits of Darkness to their true forms to join the team as the true Warrior of Darkness,.

After they defeat Cherubimon, the DigiDestined learn that the true mastermind is, an ancient and corrupt angel Digimon whom the Ten Legendary Warriors sealed away in the. The six DigiDestined must defeat his two before they scan away all of the Digital World, which would allow Lucemon to be released. Despite their efforts, Lucemon is freed and, after absorbing the Knights, digivolves into a stronger, more powerful form. The DigiDestined combine their power into a new ultimate warrior called, finally defeating Lucemon to save both the Digital World and the Real World.

Episodes
The season aired 50 episodes on in  from April 7, 2002 to March 30, 2003, then later on  and  in the  and on  in  from September 9, 2002 to July 14, 2003. Unlike the previous series, Digimon Frontier did not air in the U.K.

Digital World
The Digital World of Digimon Frontier is a in which  roam.

The Digital World is divided into ten regions, each one representative of one of the world's ten elements—Flame, Light, Ice, Wind, Thunder, Earth, Wood, Water, Steel and Darkness. A massive network of train tracks crisscross the planet, with a terminal in each region, allowing the train-like Digimon, the Trailmon, to ferry passengers from one region to the next. The most distinguishing feature of the Digital World is that everything exists in the form of fractal code—the "command code" for any data. Fractal code is usually hidden, but once it is either uncovered or has its key taken, it can be "digitized," which in turn "unlocks" the data of the item or individual in question, allowing it to be manipulated. In most cases, this leads to the data being absorbed—an action frequently perpetrated by the villains of the series. Conversely, if the Fractal Code is "rendered," it restores the data to its intended shape and form and "locks" it back into place. If a Digimon has their fractal code scanned but their data is not completely absorbed, then it will reconfigure itself into a, which then transports itself to the , where, after being tended by , it will hatch out into a new baby Digimon and start its life over again.

In ancient times, the Digital World was wracked by a massive war between the human-type and beast-type Digimon. It was then that the angel Digimon,, appeared and brought the war to an end, leading to a period of peace. Lucemon, however, eventually grew corrupted, becoming a tyrannical ruler, prompting the emergence of ten great who embodied the ten elements. After a mighty battle, the Ten Legendary Warriors were able to defeat Lucemon and imprisoned him in the "Dark Area" deep within the center of the Digital World.

Passing on into the realm of legend themselves and leaving powerful Spirits embodying their elements behind, the ten warriors were succeeded by a trinity of angelic Digimon known as the —, and. The group was not a harmonious one, unfortunately—the beast-type Cherubimon disagreed with many of the human-type Seraphimon and Ophanimon's policies, and made the argument one of the beast versus human. Mistakenly believing that the two human-types planned to betray him, the despairing Cherubimon found himself overtaken by the dark aura of Lucemon, and was transformed into a virus form. The evil Cherubimon then led the beast-type Digimon in a campaign against the human types, ultimately capturing Ophanimon and forcing Seraphimon into a regenerative coma.

To save the Digital World, Ophanimon calls upon children from Earth to merge with the spirits of the Legendary Warriors and become Digimon themselves to help free Cherubimon from Lucemon's influence. The new Legendary Warriors are eventually successful in freeing Cherubimon, but Lucemon, undeterred, soon gains enough power to consume the fractal code of the entire Digital World and destroy its moons. He then begins his conquest of Earth as well. In the last battle to save what remained of both worlds, the Legendary Warriors defeat Lucemon, allowing the Digital World and its inhabitants to be restored.

This particular Digital World is also orbited by three Digital Moons: the Red Moon, the Yellow Moon, and the Blue Moon. At least two of the Digital Moons are inhabited: the Blue Moon has the Moon Base and the Yellow Moon contains the remnants of the.

Japanese
Opening Theme: FIRE!! Artist: Kōji Wada Songwriter: Hiroshi Yamada Composer/Arranger: Michihiko Ohta

Ending Theme #1: Innocent ~Mujaki na Mama de~ (Ep. 1-26) Artist: Kōji Wada Songwriter: Chiwata Hidenori Composer/Arranger: Watanabe Cheru

Ending Theme #2: an Endless tale (Ep. 27-50) Artist: Kōji Wada and Ai Maeda (as AiM) Songwriter: Hiroshi Yamada Composer/Arranger: Michihiko Ohta

Insert Song: With The Will (Spirit Evolution Theme) Artist: Kōji Wada Songwriter: Omori Sachiko Composer/Arranger: Watanabe Cheru

Insert Song: The last element (Hyper Spirit Evolution Theme) Artist: AYUMI Songwriter: Hiroshi Yamada Composer/Arranger: Watanabe Cheru

Insert Song: Salamander (Takuya's Theme) Artist: Junko Takeuchi Songwriter: Hiroshi Yamada Composer/Arranger: Michihiko Ohta

Insert Song: in the blue (Kouji's Theme) Artist: Hiroshi Kamiya Songwriter: halta Composer/Arranger: Makoto Takou

Insert Song: Spark!! (Junpei's Theme) Artist: Masato Amada Songwriter: Matsui Kyouko Composer: Egawa Hiroshi Arranger: Michihiko Ohta

Insert Song: Kaze no Shizuku (Izumi's Theme) Artist: Sawa Ishige Songwriter/Composer: Izumikawa Sora Arranger: Watanabe Cheru

Insert Song: Say, yes! (Tomoki's Theme) Artist: Kumiko Watanabe Songwriter: Omori Shouko Composer/Arranger: Hiro Takahashi

Insert Song: Oreta Tsubasa de -With Broken Wings- (Kōichi's Theme) Artist: Kenichi Suzumura Songwriter/Composer: halta Arranger: Takoto Takou

Insert Song: Blader (Duskmon's Theme) Artist: Kenichi Suzumura Songwriter: Hiroshi Yamada Composer/Arranger: Michihiko Ohta

English
Opening Theme: A World For Us All Artist: Chris Horvath

Insert Song: Darkness In My Heart (Ep. 30)

Cast

 * -|Japanese=

All voices here are sourced to Digimon Encyclopedia: Digimon Frontier Character Cast List.
 * -|American English=