• Rider height: 200 cm. (6 ft., 5 in.)
• Rider weight: 99 kg. (218.2 lbs.)
• Ability perimeters:
  • Punching power: 3 t.
  • Normal kicking power: 10 t.
  • Maximum jump height: 15 m. (49 ft., 2 in.)
  • Maximum running speed: 100 m. per 5.2 seconds (328 ft. per 5.2 sec)
  • Sense: x10
  • Finishing Attack Power: 30 t. (Mighty Kick)

Mighty Form (マイティフォーム, Maiti Fōmu^?) is Kuuga's default form and has red armor, referred to by the police as Unidentified Life Form #4. Yuusuke was first able to transform into this form while fighting Zu-Gooma-Gu. In this form, Kuuga uses his "Mighty Kick" (マイティキック, Maiti Kikku^?) attack to kill the monsters.

• Rider height: 200 cm. (6 ft., 5 in.)
• Rider weight: 90 kg. (198.4 lbs.)
• Ability perimeters
  • Punching power: 1 t.
  • Normal kicking power: 3 t.
  • Maximum jump height: 30 m. (98 ft., 4 in.)
  • Maximum running speed: 100 m. per 2 seconds (328 ft. per 2 sec)
  • Sense: x10

Dragon Form (ドラゴンフォーム, Doragon Fōmu^?) is a azure form form that allows Kuuga to be more agile and quicker, although his physical strength is lower than Mighty Form, Dragon Form enables Kuuga to and jump quickly in order to pursue the enemy. However, it also gives Kuuga less protection, yet being better suited for quick movements and more jump power. To make up for the lack of strength, he uses the Dragon Rod (ドラゴンロッド, Doragon Roddo^?) staff as his weapon, transmorgified by using any pole or stick-like object to manifest it. His finishing move in this form is Splash Dragon (スプラッシュドラゴン, Supurasshu Doragon^?), an aerial thrust attack to the torso.

• Kuuga assumed Dragon Form in his own world while fighting against Me-Gyarido-Gi and Ra-Dorudo-Gu, destroying the former Gurongi with his Splash Dragon attack as the latter escaped. Kuuga's World
• Kuuga assumed Dragon Form in his world as he and Decade were attacked by the Hopper Riders KickHopper and PunchHopper. Kuuga's World Transcendental
• Kuuga assumed Dragon Form in the World of Decade while fighting Kamen Rider X in the Rider Battle tournament, using the Dragon Rod to coounter X's Ridol Stick. Kamen Rider Decade: All Riders vs. Dai-Shocker

• Rider height: 200 cm. (6ft., 5in.)
• Rider weight: 99 kg. (218.2lbs.)
• Ability perimeters
  • Punching power: 1 t.
  • Normal kicking power: 3 t.
  • Maximum jump height: 15 m. (164 ft.)
  • Maximum running speed: 100 m. per 5.2 seconds (328 ft. per 5.2 seconds)
  • Senses: x1,000

Pegasus Form (ペガサスフォーム, Pegasasu Fōmu^?) is a green shooting form where Kuuga's senses are heightened to extreme, superhuman levels, enabling him to see, hit and hear his opponents with deadly precision. It also allows Kuuga to detect the enemy's position, despite whatever ability they may have to avoid detection. The downside to this is that it can not be sustained for too long because of the enormous strain placed on the nervous system from over stimulation (only 50 seconds), and if Kuuga exceeds this limit, he shall be knocked back into Growing Form and become unable to transform for two hours. Kuuga uses the Pegasus Bowgun (ペガサスボウガン, Pegasasu Bōgan^?) crossbow/gun hybrid weapon that can be created out of any gun-like object, commonly Ai's hand gun. His finishing move with the bow gun is "Blast Pegasus" (ブラストペガサス, Burasuto Pegasasu^?), an arrow shot from the bowgun after pulling the hammer back to the fullest length.

• Kuuga assumed Pegasus Form in his own world to prevent Ra-Dorudo-Gu's escape. Ai gave Yusuke her hand gun and he transformed it into the Pegasus Bowgun, using the Blast Pegasus to destroy the fleeing Gurongi. Kuuga's World
• Kuuga assumed Pegasus Form in his world while fighting against Decade, the two were then attacked by the Hopper Riders KickHopper and PunchHopper. Kuuga's World Transcendental

• Rider height: 200 cm. (6 ft., 5 in.)
• Rider weight: 110 kg. (242.5 lbs.)
• Ability perimeters
  • Punching power: 7 t.
  • Normal kicking power: 10 t.
  • Maximum jump height: 10 m. (32 ft. and 8 in.)
  • Maximum running speed: 100m per 7.2 seconds (328 ft. per 7.2 seconds)
  • Sense: x10

Titan Form (タイタンフォーム, Taitan Fōmu^?) is a purple herculean form where his defense is greatly increased, allowing him to withstand most of his opponents' attacks long enough to get in close range, despite sacrificing speed. This form has much larger armor that is mainly silver with large purple trims. Although this armor provides superior protection, it still leaves parts of his body exposed, thus making him still susceptible to damage. He uses the Titan Sword (タイタンソード, Taitan Sōdo^?) that can be created out of pole or stick-like objects, or in one occasion, the sword of a fallen Grongi. His finishing move is "Calamity Titan" (カラミティタイタン, Karamiti Taitan^?), a powerful sword thrust wherein Kuuga twists the blade as it is impaled.

• Kuuga assumed Titan Form in his own world while fighting against Decade. Kuuga's World
• Kuuga assumed Titan Form while in the World of Amazon to destroy a Propheta Cruentus. The Strong, Naked, Strong Guy

• Rider height: 200 cm. (6 ft., 5 in.)
• Rider weight: 150 kg. (330.6 lbs.)
• Ability perimeters
  • Punching power: 80 t.
  • Normal kicking power: 100 t.
  • Maximum jump height: 50 m. (164 ft.)
  • Maximum running speed: 100 m. per 2 seconds (328 ft per 2 seconds)
  • Sense: x10,000

His most dangerous form, Ultimate Form (アルティメットフォーム, Arutimetto Fōmu^?) combines all the powers of the other forms, Ultmate Kuuga has a much different design colored black with gold (and a little silver) trims all over his body, as well as having five horns on the headcrest, a black belt core and spiky-looking armor.

Yuusuke assumes Ultimate Form when he fights Decade one-on-one. However, this form is black-eyed instead of red-eyed, revealed to be the result of Yuusuke losing control over his attacks when infused with Demon Imperial Powers (魔皇力, Maōryoku^?) by Kivala's bite.

This form can also utilize the powers including Pyrokinesis, along with the ability to utilize the Dragon Rod, Pegasus Bowgun, and Titan Sword, all in Rising form. However this ability was never shown along with the Ultimate Form's most powerful attack, the "Ultimate Kick" (アルティメットキック, Arutimetto Kikku^?), which is the strongest version of his Rider Kick, easily capable of destroying the entire world. In Kamen Rider Decade, Ultimate Kuuga is also capable of the Ultimate Punch (アルティメットパンチ, Arutimetto Panchi^?) finisher, a punch coated with hot flames. This form was also called the Supreme Warrior (最高戦士, Saikō Senshi^?).

• Rider height: 200 cm. (6 ft., 5 in.)
• Rider weight: 150 kg. (330.6 lbs.)
• Ability perimeters
  • Punching power: 100 t
  • Normal kicking power: 120 t.
  • Maximum jump height: 110 m. (360.8 ft.)
  • Maximum running speed: 100 m. per 1 seconds (328 ft per 1 seconds)

Unique to Kamen Rider Decade is Kuuga Rising Ultimate (ライジングアルティメット, Raijingu Arutimetto^?). Much like Kuuga's other forms that were given a "Rising" upgrade within the original Kamen Rider Kuuga, Rising Ultimate is an advanced version of Kuuga's Ultimate Form. In this form, Kuuga has a Rider Kick called the Rising Ultimate Mighty Kick (ライジングアルティメットマイティキック, Raijingu Arutimetto Maiti Kikku^?) and the flaming Rising Ultimate Mighty Punch (ライジングアルティメットマイティパンチ, Raijingu Arutimetto Maiti Panchi^?). Rising Ultimate Kuuga is first accessed in Kamen Rider Decade: All Riders vs. Dai-Shocker after Yusuke has been attacked by the Stone of Earth used by High Priestess Bishium, putting him under her control and unleashing all of Kuuga's potential. When Kuuga is under controlled of Bishium, Kuuga's eyes become the Dark Eyes (ダークアイ, Dāku Ai^?), and when Kuuga is freed of Bishium's control, the eyes change color from the Dark Eyes to the Red Eyes (レッドアイ, Reddo Ai^?). He later uses this form again in Kamen Rider × Kamen Rider W & Decade: Movie War 2010 to fight Doras thanks to Decade's K-Touch.

Decade's Final Form Ride Card allows Kuuga to transform into the Kuuga Gouram (クウガゴウラム, Kūga Gōramu^?), giving him the ability to fly. This form is used again in the World of Den-O to assist Decade and Den-O and allowing Momotaros to execute the Decade Liner (ディケイドライナー, Dikeido Rainā^?) Final Attack Ride. The Kuuga Gouram rushes toward Decade with the target stuck in his pincers while Decade performs the Mighty Kick-like Decade Assault (ディケイドアサルト, Dikeido Asaruto^?)^[1][2] flying kick towards the target. After the card is used, Kuuga can change into this form at will before Decade uses the Kuuga Final Attack Ride Card.^[3]

In Kamen Rider × Kamen Rider W & Decade: Movie War 2010, Kamen Rider Kuuga shows the ability to transform into the Kuuga Gouram without Kamen Rider Decade using the Final Form Ride Card.

In Kamen Rider × Kamen Rider W & Decade: Movie War 2010, Kamen Rider Kuuga Ultimate Form transforms into the Ultimate Kuuga Gouram (アルティメットクウガゴウラム, Arutimetto Kūga Gōramu^?), a more powerful version of the Kuuga Gouram, to fight Kamen Rider Decade Violent Emotion. However, he is soon defeated and becomes a Kamen Ride card for Decade but appears again when Decade uses the All Rider Final Form Ride Card to fight the Super Crisis Fortress. The Ultimate Kuuga Gouram can execute the Ultimate Assault (アルティメットアサルト, Arutimetto Asaruto^?), by crushing the enemy in its pincers and rushing towards a hard surface. The Ultimate Kuuga Gouram is similar to the Kuuga Gouram, though it has the color scheme and the head crest of Ultimate Form and has Black Eyes.

In Kamen Rider Battle: Ganbaride Decade uses the Kuuga Ball (クウガボール, Kūga Bōru^?) card to change Kuuga into a dodgeball-like form to perform the Decade Dodge (ディケイドドッジ, Dikeido Dojji^?) attack.

In the World of Agito, Yuusuke dons the Kamen Rider G3-X (仮面ライダーG3-X, Kamen Raidā Jī Surī Ekkusu^?) suit for a while.

• Height: 192cm
• Weight: 176kg
• Puching Power: 2.5t
• Kicking Power: 7.5t
• Highest Jump: 20m
• Top Speed: 100m/8s
• Vision and Hearing: 15km approx.
• Defense Rating: 10/10

From what was seen during Shouichi Ashikawa's past, the suit has been modified from an original version of Kamen Rider G3, using the G3's diagnostic data. All specs and performance potentials have been ramped-up. It's unknown if it has the same A.I. problem as the original G3-X, though if the G4 chip is to be any indicator, the G3-X still had something to be modified. It's newest armament, the GX-Launcher (GX-05 Cerberus), can level Grongi (and later, Unknown) with ease.

During the visit to the world of Den-O, Yuusuke was possessed by Momotaros, who uses him as a body to transform into Kamen Rider Den-O Sword Form (仮面ライダー電王 ソードフォーム, Kamen Raidā Den'ō Sōdo Fōmu^?).

• Height: 190cm
• Weight: 87kg
• Punching power: 5t
• Kicking power: 7t
• Maximum jump height: 35m
• Maximum running speed: 100m/5.2s

When possessing Yuusuke (or anyone else) or by himself, Momotaros can assume Den-O's Sword Form through the Terminal Buckle, the first and most used form in the series. When in Sword Form he uses the DenGasher as a standard sword-style weapon. This form is the most balanced among Den-O's forms, probably due to Momotaros' prominence among the other Imagin. He occasionally forms different finishers for defeating enemies, despite parts 2, 3, and 5 being similar to each other. He also uses a Special Version in I'm Born which resembles the aforementioned parts, the only difference is that Full Charge is used twice. There is also a Final Version used against the Death Imagin which uses energy from the other Taros, Sieg, and Kamen Rider Zeronos. In the Cho Den-O series Sword Form also has a triple Roundhouse Rider Kick that Momotaros dubs his "Super Finishing Attack." The DenKamen Mask resembles two halves of a peach, which is based on the story of Momotaro.