- Rider height: 200 cm. (6 ft., 5 in.)
- Rider weight: 125 kg. [275.5 lbs.]
- Ability perimeters:
Punching power: 35 t.
Normal kicking power: 50 t.
Maximum jump height: 60m (196 ft., 10 in.)
Maximum running speed: 100 m. per 5.2 seconds (328 ft. per 5.2 sec)
Sense: x10
Finishing Attack Power: unknown (Amazing Mighty Kick)
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. Originally a risk is that the user would lose control and become like Daguba, a monster bent on killing everything in its way. However, due to Godai's gentle nature, he retains his will as he uses the new form against Daguba, retaining the red eye color of Mighty Form as opposed to the original black eyed color. When in battle, Ultimate Kuuga is able to see a monster's human form, every single attack from Kuuga Ultimate causes his opponent to bleed, despite the enemy's powerful armor.
This form can also utilize the same powers as Daguba 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).
A form unique to Kamen Rider Decade is Kuuga's Rising Ultimate Form (ライジングアルティメットフォーム, Raijingu Arutimetto Fōmu). Much like Kuuga's other forms that were given a "Rising" upgrade within the original Kuuga, Rising Ultimate is an advanced version of Kuuga's Ultimate Form. In this form, Kuuga has a Rider Kick called the Rising Ultimate Kick (ライジングアルティメットキック, Raijingu Arutimetto Kikku). He also has the flaming Rider Punch called the Rising Ultimate Punch ライジングアルティメットキック, Raijingu Arutimetto Panchi) This form is accessed after Yuusuke has been attacked with the Stone of Earth by High Priestess Bishium, putting him under her control and unleashing all of Kuuga's potential. When Kuuga is freed of Bishium's control, the eyes change color from black to red. This form is used again in Decade: Final Chapter against Doras because of Decade's K-Touch.
- 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)