Moon=Millenniummon (Adventure:)

Millenniummon is an antagonist from the series Digimon Adventure:. Millenniummon was the weapon of the Dark Digimon.

Story
Before the DigiDestined arrived in the Digital World, Millenniummon was a pure destructive force that was responsible for the deaths of countless Digimon during the ancient war between good and evil Digimon. It served as a weapon for the Dark Digimon Army. However, they were unable to control its power, forcing, , , , , , , and to sacrifice themselves in order to defeat it.

Millenniummon's body was shattered into several dark crystals that spread across the Eternal Continent and the Cloud Continent. The smallest crystal also contained Millenniummon's soul, Moon=Millenniummon, which was used by and  for digivolution. The largest dark crystal, FAGA, was guarded by several, who were Millenniummon's worshippers. Because of the dark crystals, the black lightning began to strike the Eternal Continent, sending data stolen from the Internet to the dark crystals, which direct it forward to FAGA, so it can be used for creation of a new body for Millenniummon.

Moon=Millenniummon
Moon=Millenniummon is one of Millenniummon's Mega forms.

After ZeedMillenniummon was defeated in the war by, , , , , , , and , shards of its body fell back to the Digital World. One of these shards became Moon=Millenniummon.

Moon=Millenniummon devoured data from the real world and discharged it as black lightning to the Eternal Continent, where it could be used to restore Millenniummon's body and digivolve its servants into more powerful forms. For example, was able to use Moon=Millenniummon as a catalyst to digivolve  into. Devimon also used Moon=Millenniummon to digivolve itself into, and AxeKnightmon used it to digivolve NeoDevimon into.

ZeedMillenniummon
ZeedMillenniummon is one of Millenniummon's Mega forms.

In the past, ZeedMillenniummon was once the Dark Digimon's ultimate weapon, but they were unable to control it due to its immense power. However,, , , , , , , and defeated it by sacrificing themselves.