|This article is about a/an form in Kamen Rider Zi-O.|
DecadeArmor (ディケイドアーマー DikeidoĀmā) is a Kamen Rider Decade-based form accessed using the Decade Ridewatch, invoking Kamen Rider Decade's Default form. When summoned, the armor's parts are passed through the dimensional wall before attaching to the user and transforming into armor. Other Ridewatches can be inserted into the Decade Ridewatch to augment the DecadeArmor with the power of past upgrade, super or final forms.
Its visor and chest spells out "Decade" (ディケイド Dikeido) in katakana, the chest and left shoulder of DecadeArmor Build Form read "Sparkling" (スパークリング Supākuringu) in katakana, while the right shoulder reads "Build" (ビルド Birudo) in katakana.
The chest and left shoulder of DecadeArmor Ghost Form read "Grateful" (グレイトフル Gureitofuru) in katakana, while the right shoulder reads "Ghost" (ゴースト Gōsuto) in katakana.
The chest and left shoulder of DecadeArmor Ex-Aid Form R reads "Double Action XX R" (ダブルアクションＸＸＲ Daburu Akushon Daburu Ekkusu Āru) in katakana, and the chest and left shoulder of DecadeArmor Ex-Aid Form L reads "Double Action XX L" (ダブルアクションＸＸＬ Daburu Akushon Daburu Ekkusu Eru) in katakana, while the right shoulders of both forms read "Ex-Aid" (エグゼイド Eguzeido) in katakana.
The chest and left shoulder of DecadeArmor OOO Form read "Tajadol" (タジャドル Tajadoru) in katakana, while the right shoulder reads "OOO" (オーズ Ōzu) in katakana. Its Dimension Face reads "Kamen Rider OOO" (仮面ライダーＯＯＯ（オーズ） Kamen Raidā Ōzu).
The chest and left shoulder of DecadeArmor Faiz Form read "Axel" (アクセル Akuseru) in katakana, while the right shoulder reads "Faiz" (ファイズ Faizu) in katakana. Its Dimension Face reads "Kamen Rider Faiz" (仮面ライダーファイズ Kamen Raidā Faizu).
The chest and left shoulder of DecadeArmor Ryuki Form read "Survive" (サバイブ Sabaibu) in katakana, while the right shoulder reads "Ryuki" (リュウキ Ryuki) in katakana. Its Dimension Face reads "Kamen Rider Ryuki" along the bottom.
- Kamen Rider Zi-O (Zi-O Episodes 14-17, 19)
- Build Form/RabbitTank Sparkling (Zi-O Episodes 14-15)
- Ghost Form/Grateful Damashii (Zi-O Episodes 14, 16)
- Ex-Aid Form/Double Action Gamers (Zi-O Episode 16)
- OOO Form/Tajadol Combo (Zi-O Episode 19)
- Faiz Form/Axel Form (Kamen Rider Buttobasoul)
- Ryuki Form/Survive Form (Rider Time: Kamen Rider Ryuki Episode 3)
After defeating Geiz, Decade left him the Decade Ridewatch as a "trade" for nullifying the Ghost Ridewatch. Later, while fighting Another Ghost and his Gamma Commandos, Geiz gave the Decade Ridewatch to Zi-O, who used it to assume DecadeArmor for the first time. Summoning a new weapon, the Ride HeiSaber, Zi-O found that he could use a second Ridewatch in addition to Decade and so used Build, switching to DecadeArmor BuildForm. Dual wielding the Ride HeiSaber and Drill Crusher Crusher, Zi-O fought through the Gamma Commandos before engaging Another Ghost. After successively unleashing the Ex-Aid and Drive Dual Time Breaks against Another Ghost, Zi-O appropriately switched to Ghost Form. Ultimately, Zi-O performed the Ultimate Time Break which destroyed the Another Ghost Ridewatch and set Makimura free.
Fighting Kamen Rider Decade Build, Zi-O assumed DecadeArmor and appropriately switched to Build Form. Meeting Decade's Final Attack Ride with his own Final Attack Time Break, Zi-O prevailed, leading Decade to opt to revert to his default form to fight Zi-O more efficiently. Seeing Zi-O's plight, Kasshin, retainer of Oma Zi-O, enroached on their fight while he himself was engaged against Geiz, making a two-on-two battle. When Zi-O insisted that he could not become a demon king or harm Geiz, Decade sent him to the year 2068 via a dimensional wall, stripping him of his transformation in the process.
After realizing the state of the future, Sougo was faced with his future incarnation, Oma Zi-O. Refusing to accept his future as Oma Zi-O, Sougo transformed into Kamen Rider Zi-O to attack him. Assuming DecadeArmor, Zi-O unleashed, in quick succession, the Kuuga, Kiva, and Ryuki Dual Time Breaks only for Oma Zi-O to counter his past self with the matching Rider powers he possessed, overwhelming the younger Zi-O. After telling Sougo that he could only avert his future by destroying his Ziku-Driver, Oma Zi-O effortlessly forced him out of his transformation before returning Sougo to his own time.
Using Geiz's Ziku-Driver to replace his own which was destroyed, Zi-O assumed DecadeArmor Ghost Form to fight Kasshin. When Kamen Rider Decade entered the fray against Zi-O as Wizard, Zi-O summoned the Parka Ghosts of Goemon and Billy the Kid to retrieve the replacement Ziku-Driver from Uhr so he could give it to Geiz, who joined him with the Ex-AidArmor. Evenly matched against Kasshin and Decade, Zi-O and Geiz pushed their advantage by exchanging Ridewatches, with Zi-O switching to the two-man DecadeArmor Ex-Aid Form L and R wielding the Zikan Girade and Ride HeiSaber respectively while Geiz assumed GhostArmor. The two Zi-Os proceeded to engage Decade, who soon retreated through the dimensional wall as he was outmanned.
When Time Jackers Uhr and Ora boarded their Time Mazines to attack the Kamen Riders, Zi-O L boarded his own Time Mazine alongside that of Geiz while Zi-O R continued the fight against Kasshin. Taking their fight to the vortex, Zi-O L and Geiz soon defeated Uhr and Ora while Zi-O R performed the Ultimate Time Break to ultimately destroy Kasshin.
Fighting Another Shinobi alongside Geiz, Zi-O assumed DecadeArmor and struck Another Shinobi with the Blade Dual Time Break. This was followed by the Ryuki Dual Time Break, only for Another Shinobi to counter and reflect Zi-O's attack back at him with a cyclone, forcing Zi-O back to his default form.
Fighting Another Quiz alongside Geiz, Zi-O assumed Decade Armor OOO Form while Geiz assumed Ex-AidArmor. Together, their performed their respective Rider Kicks only to be frozen in time by the Time Jacker Ora, who moved the two Riders so that they were aiming at each other before taking her leave with Another Quiz. When the flow of time resumed, Zi-O and Geiz struck each other with their finishers, forcing them out of their respective transformations.
- "(Digital beeping accompanied by cards being blown away) D-D-D-Decade!"
- ―Activation announcement[src]
- "(Right-hand Ridewatch's announcement)! Armor Time! (Upbeat rock music) KamenRide! Wow! Decade! Decade! Deca~de! (KamenRide: Decade transformation noises)"
- ―Rider Armor transformation announcement[src]
- "Finish Time! Decade! Attack Time (Break/Burst)!"
- ―Rider Armor finisher announcement[src]
- "Final Form Time! (Kamen Rider)!"
- ―Rider Armor upgrade announcement[src]
- "(Kamen Rider)! Final Attack Time Break!"
- ―Rider Armor upgrade finisher announcement[src]
- "Ka-Ka-Ka-Kamen Rider!"
- ―Miridewatch insertion announcement[src]
- Main article: Ride HeiSaber
- B-B-B-Build Final Attack Time Break (ビ・ビ・ビ・ビルドファイナルアタックタイムブレイク Bi-Bi-Bi-Birudo Fainaru Atakku Taimu Bureiku): Zi-O performs an enhanced version of the Vortex Time Break in which a small, red and blue, hourglass-shaped vortex appears before kicking the enemy.
- Both Zi-O's DecadeArmor form and Ghost's Toucon Boost Damashii form follow a similar theme for their special abilities. Both utilize their respective collectible devices to adapt different powers and abilities from their other Rider Forms to their own, and both give their Rider access to a higher grade of weaponry (i.e. Ride HeiSaber for Zi-O/Sunglasseslasher for Ghost).
- The design and function of the Decade Head Gear M is reminiscent of the Ganbarider's helmet design. Both armaments utilize a monitor-theme and feature a face screen which displays a 2-dimensional image of the Rider's face.
- The DecadeArmor's Dimension Face displays the Rider's face in proportion to their actual helmet size and uses a Rider Card-style template in its display. Ganbarider's helmet also displays the Rider's face, but uses a unique face filter-style display. This function extends to variations and form changes.
- Kamen Rider Ghost's Grateful Damashii form was chosen as the basis for the DecadeArmor Ghost Form instead of the Toucon Boost Damashii form, which is Ghost's actual, next point of progression from the Ore Damashii. This is the only instance thus far where the proper power-up form was skipped.
- This is also similar to how Ex-Aid's next form was a Fusion Form, which was followed by the Upgrade Form used for DecadeArmor Ex-Aid Form: Double Action Gamer Level XX.
- While likely a coincidence, all Final Form Armors use forms with armor, an undersuit, or both, which makes sense given forms like Grateful Damashii lack something that would be difficult to replicate without clashing with the upper-body armor.
- Final Form Armor has the distinction of not sharing the design of standard Rider Armor, instead, possessing the original design of the Form used by the Rider, with the only constant difference being the chest armor, shoulder armor, and helmet from DecadeArmor, and the Mid Band Liner M that vertically spans the torso of any form used by Zi-O.
- The barcode of DecadeArmor's main form has the numbers "2009 453145" underneath it. 2009 references the year Kamen Rider Decade debuted on TV, while the other numbers are the numerical order of letters in the alphabet which when deciphered spell out "D-E-C-A-D-E".
- Despite DecadeArmor is used for upgrading the Rider power into super form, those who lacked such power-up (eg. Ryuki and Kabuto) are given their final forms altogether.
- Kamen Rider Zi-O
- Tsukasa Kadoya - Original Kamen Rider Decade