Ultima Weapon

The Ultima Weapon (アルテマウェポン) is a Keychain for Sora's, Data-Sora's, Riku's, Terra's, Ventus's, and Aqua's Keyblades introduced in Kingdom Hearts. It is one of the most powerful Keyblades, and requires an incredible amount of effort to obtain in each game. Unlike other Keychains, each game's version of the Ultima Weapon has a different design, and shares only the name and the phenomenal quality of its stats.

Design
The Ultima Weapon Keyblade is named after the eponymous sword in the Final Fantasy series. The Ultima Weapon is typically shown within the Final Fantasy series as a long sword, with a glowing blue/white blade and a golden handle. It is usually the strongest weapon for the main protagonist in the games it appears in.

The Kingdom Hearts version of the Ultima Weapon is strongly reminiscent of the Dream Sword, but is wrapped in an ornate gold filigree in a pattern slightly reminiscent of fish bones. The teeth of the blade are a golden version of the crown charm Sora wears, and the Keychain token, attached to the blade by shimmering thread, is a gilded heart, used throughout the series to refer to a complete being, instead of a Heartless or Nobody. It also bears one heart just above the guard and another just next to the crown making up the teeth of the blade, both of which are present in the Kingdom Hearts II version. In the game, the blade's size is smaller compared to the hilt, compared to its design in the official artworks. This version is also used in Kingdom Hearts: Chain of Memories and Kingdom Hearts Re:coded. Small circular ripples of bolts and light emit whenever Sora strikes a target with it.

The Kingdom Hearts II version retains most of its Kingdom Hearts version elements, except for the colors (blue, white and gold), the crown-and-heart keychain, and the Dream Sword. It also includes many more crowns into its design, including one at the tip of the blade, near the crown "teeth", two making up the guard, three in the chain, and the aforementioned combination of a crown and the original heart Keychain as the token. Also, its sound effects when striking a target are also different from the previous game, and often involves crown motifs.

The Kingdom Hearts Birth By Sleep version has elements from both previous Kingdom Hearts games. Its style is similar to the Kingdom Hearts version, but its color scheme is similar to the Kingdom Hearts II version. It also uses stars and the Wayfinder design instead of crowns and hearts. It is mostly a pale, almost glowing blue with white and gold. The teeth and Keychain are a blue Wayfinder, similar to Aqua's, with the original heart in the middle instead of the Terra's Mark symbol.

The Kingdom Hearts 3D: Dream Drop Distance version has the design similar like the first Kingdom Hearts game with minor changes. The color scheme is somewhat a combination between the first and second Kingdom Hearts games, as it has yellow on the blade connector, and the teeth and light blue color on the guard and the filigree ornament. The teeth is a Spirit Dream Eater's emblem within a crown. The keychain is a variation on the Kingdom Hearts II heart and crown design, except with the heart above the crown. The sound effects used when striking targets with it is taken straight from Kingdom Hearts II as well.

Kingdom Hearts
Ultima Weapon can be synthesized once the fifth list is unlocked.
 * 5 Lucid Gem
 * 5 Power Gem
 * 5 Thunder Gem
 * 3 Mystery Goo
 * 3 Gale

Kingdom Hearts Final Mix
Ultima Weapon can be synthesized once the sixth list is unlocked.
 * 5 Thunder Gem
 * 5 Mystery Goo
 * 3 Serenity Power
 * 3 Stormy Stone
 * 3 Dark Matter

Kingdom Hearts II
The Ultimate Recipe is found in a chest at the Mansion: Basement Corridor. The Ultima Weapon is a rank S synthesis item that provides 119 EXP. An Energy Crystal is required to reduce the Orichalcum+ required for synthesis, as there are only 7 in the game; this means that the Ultima Recipe cannot be synthesized unless the Moogles are at least level 2. As Serenity items are part of the recipe, they cannot be used to upgrade it.
 * 13 Orichalcum+
 * 1 Orichalcum
 * 1 Mythril Crystal
 * 1 Dense Crystal
 * 1 Twilight Crystal
 * 7 Serenity Crystal

Kingdom Hearts: Chain of Memories
Sora can obtain the Ultima Weapon card in a Castle Oblivion Bounty room after both games are cleared.

Kingdom Hearts Birth by Sleep
Terra, Aqua, and Ventus can obtain the Ultima Weapon after clearing Villains' Vendetta in the Mirage Arena.

Kingdom Hearts Re:coded
Data-Sora can purchase the Ultima Weapon for 1500000 SP from the System Sector in Hollow Bastion's Entrance Hall (UL).

Kingdom Hearts 3D: Dream Drop Distance
Sora and Riku can obtain the Ultima Weapon by defeating Julius.

Gameplay
In Kingdom Hearts, it is the strongest Keyblade in terms of strength and MP and even stronger in Final Mix, as well as in both games being the most difficult to deflect (in fact, impossible) and having one of the longest reaches. However, a Keyblade like the One-Winged Angel tends to rival it in power through other means (such as the most powerful critical hit damage in the game).

However, it is subsequent games onward that most of the time, the Ultima Weapon is mainly on par with others, and is often a more balanced choice between several of the final weapons to be obtained; usually in terms of both strength and a solid focus in magic, turning it into one of the more well-rounded final weapons of the series.

In Kingdom Hearts II, it is second in strength to the Fenrir and second in magic to the Fatal Crest. In Kingdom Hearts II Final Mix, it is third in magic to Winner's Proof. However, its MP Hastega ability is much more useful in normal combat than the abilities attached to these other Keyblades, making it a good choice for magic users and physical combat alike. In Kingdom Hearts Birth by Sleep, its physical strength is second to Void Gear and Royal Radiance and third to Terra's Chaos Ripper, and is equal to Aqua's Master's Defender. Its magic strength is surpassed by the No Name, Brightcrest, Royal Radiance, and Master's Defender, and equaled by the Pixie Petal. In Kingdom Hearts 3D: Dream Drop Distance, it is second in strength and Reality Shift triggers to the Unbound and is tied with End of Pain in terms of magic.

Other appearances
Both the Kingdom Hearts and the Kingdom Hearts II versions of Ultima Weapon were released with three other Keyblades in a special Play Arts Figures accessory set, Play Arts Arms.

Through the use of a cheating device, textureless versions of the Ultima Weapon can be obtained in Kingdom Hearts II. These are the "Edge of Ultima", a version of the original Ultima Weapon with a glitched appearance, and the "Detection Saber", a second copy of the original as well, except slightly larger. When these Keychains are accessed in Sora's Items menu, no picture of the Keyblades are shown, only map icons.

Kingdom Hearts 358/2 Days
While not appearing as a Keyblade, Ultima Weapon appears in Kingdom Hearts 358/2 Days as an Ability Panel that raises the Strength of the user's equipped weapon. It can be redeemed for 255 Challenge Sigils at the Moogle Shop.

Trivia

 * Coincidentally, there are also other Keyblades modeled after the signature Ultima Weapon's design as well, with them utilizing a type of sword as their cores.