Digimon Frontier: Island of Lost Digimon

Island of Lost Digimon is the the 7th film of the TV-based Digimon movies, and not in continuity with the show. It is also the only one shown featuring the characters from Digimon Frontier.

Overview
Takuya and company ended up on a floating island in the middle of a civil war between Human Digimon (who Takuya, JP, and Tommy take sides for) and Beast Digimon (who Koji and Zoe take sides for), instigated by an evil Digimon named Murmuxmon. Murmuxmon was posing as the leader of each side in the war so that he could free an ancient evil - known as Onismon - that the Ancient Warriors, AncientGreymon and AncientGarurumon had defeated. The team then tries to end the war but it is too late and Onismon is resurrected. However he is soon after defeated by the also resurrected AncientGreymon and AncientGarurumon. The movie ends with the 2 sides finally making peace.

Characters
Bearmon

is one of the Beast-type Digimon who live on the Wandering Island, where his race constantly war with the Human-type Digimon also living there. His elder brother, Grizzlymon, is the general of the Beast army. However, Bearmon hates the fighting, because he is secretly best friends with Kotemon, one of the Human Digimon.

Koji Minamoto and Zoe Orimoto wind up in the Beast village, where Bearmon takes care of them, telling them about the conflict. When the DigiDestined are reunited, the kids begin to take sides themselves, each having seen the war from one side's point of view. Bearmon and Kotemon reveal their friendship to the kids and, as a "reward" for not fighting amongst each other, take them to a cave they had found bearing the symbol of Ornismon, the protective spirit of the island. They are found by Grizzlymon and Dinohyumon, who begin to fight each other, only to be stopped by KendoGarurumon and Agunimon, but Grizzlymon and Dinohyumon force he and Kotemon to stop meeting.

When the war reaches a critical point and a massive battle begins, Bearmon and Kotemon help Bokomon, Neemon and Tommy Himi to reassemble the shattered hieroglyphics in Ornismon's chamber, only to discover that the ancient Digimon was not a protector at all but an evil force – one which was then unleashed by Murmuxmon, who had fostered the conflict on the island to gather the necessary amount of Fractal Code to revive Ornismon. Kotemon begged for AncientGreymon and AncientGarurumon to save them, only to be destroyed by a blast from Ornismon. Bearmon screamed his name and two Ancient Warriors were reborn, using their power to defeat Ornismon once and for all. In the wake of the DigiDestined's departure, Bearmon was reunited with the reborn Kotemon and they made a mural of the DigiDestined on the cave wall.

Dinohyumon

was the second-in-command of the Human-type Digimon on the Wandering Island and rival of Grizzlymon. He was first encountered by the DigiDestined as he routed a Beast-type Digimon attack on the Human-type settlement in vain. Later, when attempting to drive Bearmon, a friend of his younger brother Kotemon, away, he got into a big fight with Grizzlymon. Agunimon stopped Dinohyumon, who tried to recruit him in preparation for the impending climactic battle. Takuya agreed, as part of the DigiDestined's plan to stop the fight.

When Zoe Orimoto and J.P. Shibayama revealed the connection between the two faction's leaders, Dinohyumon challenged their claim but Takuya countered by asking him where Darcmon was, forcing HippoGryphomon to transform into Darcmon before Dinohyumon's eyes and revive Ornismon. Spurred on by Kotemon’s sacrifice, Dinohyumon and Grizzlymon joined forces and had their armies weaken Ornismon, allowing AncientGreymon and AncientGarurumon to destroy the demon bird once and for all. With the Wandering Island back on the Digital World, Dinohyumon gave his thanks to the DigiDestined and apologized for his actions.

Grizzlymon

was the second-in-command of the Beast Digimon on the Wandering Island and got his orders from HippoGryphomon. When fighting with Dinohyumon to separate his little brother, Bearmon, from Dinohyumon's brother, Kotemon, Takuya and Koji intervened as Agunimon and KendoGarurumon. Grizzlymon requested that Koji fight for the Beasts. When J.P. and Zoe tried to convince Grizzlymon and Dinohyumon that HippoGryphomon and d'Arcmon were the same being, Grizzlymon ignored them until HippoGryphomon appeared and it turned out that both were the forms for Murmuxmon, who needed the energy from the Digimon to revive Ornismon. Grizzlymon and the Beast Digimon and Dinohyumon and the Human Digimon combined their powers and were able to weaken Ornismon enough for AncientGreymon and AncientGarurumon to destroy him. After that, Grizzlymon and Dinohyumon apologized and thanked the Legendary Warriors for restoring peace between the Human Digimon and the Beast Digimon.

Kotemon

was among the Human Digimon whose older brother was Dinohyumon. He was friends with Bearmon but their older brothers refused to let them hang out. During the part where Murmuxmon (who had been disguised as d'Arcmon and HippoGryphomon) had released Ornismon, Kotemon sacrificed his life to bring AncientGreymon and AncientGarurumon back to destroy Ornismon. His Digi-Egg is kept by Bearmon and it is shown in the credits that he was eventually restored.

Villains:

Ornismon is an ancient Digimon who was sealed away by AncientGreymon and AncientGarurumon in ancient times when he terrorized the Digital World. When the villainous Murmuxmon heard of him, he planned on reviving him to get revenge on the ones who banished him to the Wandering Island. To do so, Murmuxmon unleashed a war between the human form and beast form Digimon on the island to get many Digi-eggs which would help him revive Ornismon. Although the DigiDestined found out what he planned, it was too late and Murmuxmon was able to revive Ornismon. The two then went on a killing spree on the wandering island but the DigiDestined as well as the tanks of both factions were able to cause some damage to the powerful Digimon. Bearmon's prayers finally allowed AncientGreymon and AncientGarurumon to appear and they destroyed Ornismon, this time for good.

Murmuxmon is an evil Digimon who was banished on the Floating Island. It is there that he learned about the ancient monster Ornismon and started the war between the Human Digimon (leading them as Darcmon) and the Beast Digimon (leading them as HippoGryphomon) for the purpose of extracting enough data born of hatred to revive Ornismon and conquer the Digital World to have his revenge. He is ultimately destroyed by Agunimon.

Trivia

 * This movie is not in continuity to the series, mainly because Zoe Orimoto has her Human Spirit. Since this movie takes place between Episodes 12 and 13, she should not be in possession of her Human Spirit yet.
 * Ironically, while the three previous Digimon movies use the US Frontier opening theme, this movie does not.