While it is not known to evolve into or from any other Pokémon, Arceus will change type and form when it is holding a Plate or type-specific Z-Crystal.
Like Darkrai and Shaymin before it, Arceus was not officially recognized by Nintendo until February 14, 2009, the year of its debut movie. It was officially revealed to international audiences on August 3, 2009.
Arceus is a white, equine Pokémon with an androgynous appearance. It resembles a qilin or centaur with a gray, vertically-striated underside. The striated pattern has similar recurrences on the underside of its mane, tail, and face. Its four pointed feet are tipped with gold hooves. Its long mane juts away from its head, and its face is gray, with green eyes and red pupils, and a green circular pattern below its eyes. Arceus also has a streak of gold coloration on its head and ears that point upward. Its neck is fairly long, with two pairs of extrusions to the sides, and a flap-like feature on the neck's underside that is colored white like much of the body. Arceus also has a golden cross-like wheel attached to its body by its round abdomen, which changes color along with its eyes and hooves based on its current type, which depends on the Plate or type-specific Z-Crystal that it wields. The wheel also has four jewels attached to it. The pattern of striated gray of Arceus's underbelly resumes past Arceus's waist. Its limbs have gray undersides and extrusions at the tops of the legs. Arceus's tail is fairly like its mane in terms of shape and coloration. Despite its quadruped appearance, Arceus is capable of flight.
According to legend, it shaped the Pokémon universe using its 1,000 arms. Arceus has been referred to as "The Original One" in myths and legends and is generally considered to be one of the strongest Pokémon. Arceus is thought to have created Sinnoh and Ransei, and possibly the entire Pokémon universe, along with the lake guardians, Uxie, Azelf, and Mesprit, as well as the Pokémon of Myth, Dialga, Palkia, and Giratina. Because of this, Arceus is thought to be one of the most long-lived of all Pokémon species. It has the power to recreate the Pokémon of Myth as well, presumably to guard the dimensions when a Trainer has caught one of them. In the anime, Arceus has been portrayed as having powers such as bringing back things that it once destroyed, making certain things vanish into thin air, halting time, and overturning the very laws of nature. The anime has also shown that Arceus has the power to not only calm Dialga and Palkia but also destroy the Red Chain. Arceus can change its type at will in order to adapt to a situation, as seen with its use of Plates (including the Legend Plate) or Z-Crystals. Arceus also has the power to split up into two, creating a piece of itself to exist outside of its home dimension which is also implied to be its physical form, being only a piece of its whole being, while its true form is unknown and incomprehensible.
Arceus is shown to care for and safeguard the planet in ancient times and protected it from cataclysms such as meteors, and it would show gratitude and compassion in return to those who treated it with equal kindness. In the modern time, Arceus continues to watch over the world, and it wishes for people and Pokémon to work together in the face of adversity. Even when it is needed, it would only give out hints for how to solve the problem, instead of directly interfering. In Pokémon Legends: Arceus, it is explained that Arceus can give its blessing to Pokémon to make them more powerful, which are referred to as noble Pokémon and Ride Pokémon, and the power is passed down through family lines. The people of Hisui worshipped the noble Pokémon. Arceus can also create items for humans to use, such as the Arc Phone. Arceus does not suffer fools gladly, and it will attack in a violent rampage if betrayed or deceived. It also holds long grudges if betrayed by those it considered friends. In Arceus and the Jewel of Life, it is said to "feed" off the energy of the elemental plates. Arceus has the power to appear in dreams and create a variety of Pokémon to serve as challenges as seen in Eternal Battle Reverie.
In the introduction sequence of Pokémon Legends: Arceus, Arceus was capable of taking the form of a glowing, white silhouette, it was shown to be capable of human speech, and it states that Arceus is simply the name humans call it. The first ancient inhabitants of the Hisui region, the Celestica, worshiped it, referring to it as "almighty Sinnoh" and "great Sinnoh". Arceus also had the title "might of Sinnoh", with the term Sinnoh later on becoming the name of the region. The Diamond Clan and Pearl Clan also worship it, though they mistook Dialga and Palkia, respectively, for Arceus.
Arceus debuted in Arceus and the Jewel of Life. It was angry at the people of Michina Town for Damos's unwitting betrayal of it in ancient times, and so it attempted to destroy the world. When Ash, his friends, and Sheena were teleported by Dialga to ancient times, they directly influenced the event, changing the future for the better so that Arceus will stop its destruction.
Arceus made its main series debut as a silhouette in Showdown at the Gates of Warp!. It was called upon by Ash, his friends, their alternate world counterparts, and the people in both of their worlds to help stop Dialga and Palkia's fight and destroy the Red Chain that was forcing them to battle.
Arceus appears as a central character in the Arceus and the Jewel of Life manga adaptation, reprising its role from the movie. After Arceus saved the world from a meteor, Damos took care of it. It gave Damos the Jewel of Life to make the land of Michina Town rich and fertile. Damos then "betrayed" Arceus, and it has been outraged ever since.
Arceus appears in the TCG in all types but Dragon and Fairy, and a player can have as many Arceus cards in their deck as they like, unlike all other cards in the game (besides Basic Energy cards). Cards based on Arceus first appeared in the Arceus expansion set.
Pokémon Super Mystery Dungeon: Arceus appears when Dark Matter begins trying to take the Tree of Life to the sun, leading the other Pokémon in attempting to stop its ascent. He is able to telepathically reach the player thanks to Mewtwo and transports them to the Tree of Life's roots to confront Dark Matter. When Dark Matter regenerates itself and sends out a massive shockwave, Arceus and the other Legendary Pokémon gathered to stop the Tree of Life are immediately turned to stone. After Dark Matter is defeated, Arceus will remain at the top of Destiny Tower.
Arceus has multiple different forms that it switches between with its AbilityMultitype, with each of its forms having a different type. In total, it has eighteen different forms, one for each type. Though most of its forms were introduced in Generation IV, its Fairy-type form was introduced in Generation VI, along with the Fairy type as a whole.
In games besides Legends: Arceus, Arceus's signature moveJudgment is Normal-type by default, but changes to match the type of the Plate that it holds (being unaffected by Z-Crystals). In Legends: Arceus, the type of Judgment is directly determined by Arceus's form, such that its type always matches that of Arceus; additionally, Arceus can change its form during a battle using the Legend Plate. After being exposed to the Legend Plate, it will be in its Normal-type form by default and change its form before using Judgment to have a type advantage over the target, which also changes Judgment's type to match Arceus's. When determining the type that it changes into, any double weaknesses that the target may have are prioritized, followed by a type that resists the target's primary type (prioritizing immunities), then a type that resists the target's secondary type (again prioritizing immunities); if multiple types are equally valid, one of them is chosen at random. Arceus reverts back to its Normal-type form when the battle ends. If Arceus is deposited into Pokémon HOME while in any of its alternate forms, it reverts to its Normal-type form; if it is under the effects of the Legend Plate when deposited into HOME, these effects wear off.
In the Generation IV games, there is an unused ???-type Arceus, but it cannot be legitimately obtained in the games, as there is no ???-type Plate. Due to how its Ability would automatically turn any Arceus without a Plate into the Normal-type in Generation IV, a ???-type Arceus hacked into the game will be treated as Normal-type. This form was removed in Generation V due to the removal of the ??? type.
Arceus and Silvally have similar Shiny colorations, which both depict them as being yellow instead of white, likely as a reference to Arceus.
In Generation IV (its debut generation), it was impossible to legitimately give Arceus more than 100 EVs in any stat (without the use of glitches), since it was only ever distributed at level 100. Prior to Generation V, level 100 Pokémon could not gain EVs through battling because they could not gain experience.
Arceus is the only pre-Generation V Pokémon to never officially receive a DPBP number. Kadabra, which was not released as a TCG card during the DPBP era, is assumed to be #070, as Abra and Alakazam are #069 and #071, respectively.
Arceus received the most votes of all pre-Generation V Pokémon in the Pokémon Global Linkpromotion poll in both the Japanese poll and the international (non-Japanese and non-Korean) poll.
Prior to Generation VII, Arceus was classified by Pokédex color sorting as gray.
The official English website of Pokémon Legends: Arceus used to refer to Arceus as a Legendary Pokémon, which was later corrected to Mythical Pokémon. In the Japanese website, it has been referred to as a Mythical Pokémon from the beginning.
Arceus appears to be particularly based on a creator deity, present in many world cultures. Arceus's stance and general form are similar to Egyptian bull and calf idols, particularly Apis. Based on its appearance and attack movements in the 3D games, Arceus may be modeled after a llama, horse or qilin. The arc on its back may be inspired by the Dharmachakra, or the Bhavacakra, used to represent a concept similar to the reincarnation in Hinduism. It also resembles a stylized halo, a form of religious iconography used by many religions to indicate holy, divine, or sacred figures; it has at various periods also been used in images of rulers and saints.
The conception of the first god might be influenced by the Shinto gods Kuninotokotachi and Amenominakanushi, who summoned Izanami and Izanagi to create Japan with the spear. It may also be a reference to the qilin, a Chinese mythical creature. Its myth is nearly identical to the world egg, found in creation myths of many cultures and civilizations. Arceus may also represent or be inspired by the bodhisattvaAvalokiteśvara, who, in Buddhism, is either pictured with eleven heads and one thousand arms (the latter of which is mentioned in Arceus's Pokédex entry) or in a white, four-armed manifestation (which could look similar to Normal-type Arceus).
Arceus may be a combination of αρχή arkhé (Ancient Greek for origin and authority) or alpha and deus (Latin for god) or Zeus (king of the gods in Greek mythology). It may also involve arcane, aureus (Latin for golden), arc, arcesso (Latin for I summon), Archeus (an aspect of the astral plane), or Chaos (the origin state of the universe in Greek mythology, often personified as the first primordial deity).
Arceus itself says that its true name has no equivalent in human language.