Arceus (Japanese: アルセウス Arceus) is a major character in the third Diamond & Pearl series movie, Arceus and the Jewel of Life.
Arceus made its debut in Arceus and the Jewel of Life. Thousands of years in the past, when the world was threatened by a meteor, Arceus summoned all of its power and tackled the massive rock, destroying it. However, in the process Arceus lost the sixteen Plates that gave it life and began to die. At this time Damos discovered the dying Pokémon, then found one of the missing Plates and returned it, giving Arceus strength to pull back the others and thus fully recover. In gratitude for Damos's actions, Arceus detached five of its Plates and formed theJewel of Life, which it loaned to him in order to make the desolate wasteland of Michina Town rich and fertile.
Arceus did, however, stipulate that the Jewel of Life had to be returned. The date was the next solar eclipse - an event that was a harbinger of Arceus's appearance - but when Arceus appeared to reclaim the Jewel, Damos viciously attacked it with the intent to kill, much to its abject shock. Arceus managed to fight off the attack and counter, killing Damos, then it went into a deep sleep, vowing to judge humanity when it next appeared.
In the present day, Arceus's imminent awakening caused distortions in the Spatial and Temporal dimensions. Therefore, Dialga and Palkia, believing that the other had invaded its territory, battled over Alamos Town.
Its next appearance came in the era of Ash and his friends, in which it appeared in Michina Town and began passing down its Judgment to destroy the area. Sheena attempted to return the Jewel of Life in this era but inadvertently gave it a fake (which had been created to further prevent it from retaking the real Jewel), making it even angrier. When the creation trio appeared to protect the world from Arceus, Palkia restrained it while Dialga sent the heroes back in time to Damos's betrayal.
In the ancient past, the group discovered that Damos was controlled by another man, Marcus, who had grown bitter with his belief that returning the Jewel of Life to Arceus would result in Michina Town once again becoming desolate and wished to destroy it to prevent such events, making them realize that the legend of Damos's betrayal was a lie. By manipulating Sheena, Marcus nearly succeeded in killing Arceus and permanently altering the fabric of space-time (nearly destroying Ash and all the other heroes except Damos in the process). Fortunately, Damos managed to reach the last bit of life in Arceus's heart, giving it enough strength to re-absorb the Jewel of Life from Ash, saving it from certain death. It then revived the heroes, and they returned to the future. Although Arceus was still furious when they returned, the past finally caught up with the present, and it remembered Ash's role in saving its life, thus soothing its rage and, as it later remarked, making it feel part of the world Ash and the others lived in for the "first time."
- Arceus's Plates appear as a single color and are brick-shaped in the games, but in the movie, they are coffin-shaped and glow in rainbow colors. However, in the episode Journey to the Unown!, they appear as they do in the games.
- According to ADR director Tom Wayland, Arceus was originally going to be voiced by actor Vincent D'Onofrio of Full Metal Jacket and Men in Black fame. However, before his recording session, there were difficulties with D'Onofrio's agent and he was unable to record for the movie. After re-auditioning, Tom Wayland himself was chosen to voice Arceus instead.