"It's no use. However hopeless it'll be, the light in people's hearts will never disappear!"
- ―Daigo (as Ultraman Tiga) to Giant Black Silhouette
Great Decisive Battle! The Super 8 Ultra Brothers
After Daigo realized his dream to become an astronaut, a light grants him the Spark Lens and becomes Ultraman Tiga. As the giant rises, the whole city begins to support him as he fights King Silvergon and King Goldras. Though Tiga gains the upper hand at first but only to be captured in Super Alien Hipporito's cylinder. Asuka and Gamu then also remember their own hopes and dreams with the help of Ryo and Atsuko which enable them to transform into Dyna and Gaia. The two giant later frees Tiga from Hipporito's prison and fights the two monsters. With both King Silvergon and King Goldras defeated, Super Alien Hipporito appears and attacks. The alien finally met his end when Tiga fires his Zepellion Ray.
However, the mysterious cloaked being and many other similar looking beings use their magic to revive the souls of the defeated monsters. The souls combine to form Giga Khimaira. The monster knocks down the three Ultras, however, their friends and the city continuously cheer them on and they rise up to right Giga Khimaira. Soon, Hayata, Dan, Goh, and Seiji transform into the Ultra Brothers with the help of their wives. Together, they free Ultraman Mebius from his imprisonment. The five then join Tiga, Dyna, and Gaia help fight Giga Khimaira. After repelling several attacks from Giga Khimaira, it flees into space. The Super 8 Ultra Brothers follow it and finish it off. However after returning to Earth, the cloaked beings once again rise.
The mysterious beings, called Black Silhouette, fuse to become the Giant Black Silhouette. The Giant Black Silhouette states that he will make more powerful monsters and bring despair to Earth. Tiga however replies back that it's useless and that the light in everyone's heart will always protect them. The Super 8 Ultra Brothers combine their powers to use the Superior Myth Flasher and destroy the Giant Black Silhouette.
After the decisive battle, Daigo soon marries Rena. Together with the others, they travel to Nebula M78. However, it was unknown whether Daigo still has the Spark Lens since the threat of Black Silhouette had ended.
- Home World: Planet Earth (Superior Universe)
- Height: 53 m
- Weight: 44,000 t
- Time Limit: None demonstrated
- Tiga Crystal (ティガクリスタル Tiga Kurisutaru): The crystal on Tiga's forehead is used to manipulate light energy for various techniques.
- Eyes: Tiga possesses natural night vision as he can see just as clearly in the dark as he can in bright light.
- Protectors (プロテクター Purotekutā): The yellow bands on his upper body, they are indestructible pieces of armor, the sturdiest portions of his anatomy.
- Color Timer (カラータイマー Karā Taimā): A standard Color Timer, but unlike its Neo Frontier counterpart it is green in color and shows no sign of a time limit.
- Ultra Armor: Tiga's skin can withstand high heat environments and low temperatures. It is does not show scratches and is resistant to fire and beams.
- Arms: Presumed to be used similar to the original Ultraman Tiga's.
Daigo raises the Spark Lens to the sky and activates by shouting "Tiga!". The Spark Lens' wing like "appendages" then opens and light shines from within transforming Daigo into Tiga.
Multi Type (マルチタイプ Maruchi Taipu) is Tiga's default form, which has equal parts of strength and mobility. Its main body colors are silver, red and purple. This form is assumed to have the same powers as the original Tiga's form of the same name. As he did not have much on-screen time, many of his abilities are still unknown.
- Flight Speed: Mach 5
- Running Speed: Mach 1.5
- Underwater Speed: Mach 1.5
- Burrowing Speed: Mach 1.5
- Jumping Distance: 800 m
- Grip Strength: 50,000 t
- Zepellion Ray (ゼペリオン光線 Zeperion Kōsen): Ultraman Tiga's signature move. It is performed when Tiga makes V-shaped arm cross arm formation, charged using the arms by spreading them open and drawing them backwards, creating a line of light to consolidate energy before he performs an L-style beam. It can destroy monsters in one shot.
- Like his original counterpart, Tiga is able to fire a non-charged variant of the Zepellion Ray. This was used to knock Super Alien Hipporito out of the sky.
- Ultra Grand Wall (ウルトラグランドウォール Urutora Gurando Uōru): A combination shield that can reflect enemy attacks.
- Excellent Reflection (エクセレント・リフレクション Ekuserento Rifurekushon): An energy wave used to repair the damages done by Giga Khimaira.
- Ultra Superior (ウルトラスペリオル Urutora Superioru): Tiga and the other Super Ultra Brothers fire their respective finisher attacks.
- Illusionic Slugger (イリュージョニック・スラッガー Iryūjonikku Suraggā): When a blue variant of the Ultra Superior is fired at the Eye Slugger, it can can multiply into many copies.
Glitter Version (グリッターバージョン Gurittā Bājon) is Tiga's final form. Compared to the original's counterpart of said form, this form was born from mankind's hope to defeat the Giant Black Shilloute.
- Glitter Zepellion Ray (グリッターゼペリオン光線 Gurittā Zeperion Kōsen): Tiga's "L" Style finisher. It is an upgraded version of his Multi Type finisher.
- Superior Myth Flasher (スペリオルマイスフラッシャー Superioru Maisu Furasshā): A combination attack where the Super 8 Ultra Brothers fire their respective finisher attacks.
- The Great Decisive Battle! The Super 8 Ultra Brothers movie was the last time Hiroshi Nagano reprises his role as Ultraman Tiga's voice actor.
- Ultraman Tiga's grunts and voices were provided by Hiroshi Nagano in conjunction with Daigo's speaking voice since The Final Odyssey until this movie. However in some instances, such as when Tiga flew and chased Super Alien Hipporito, his grunt was used by Yuji Machi's. His grunts are the exact same ones used in Ultraman Tiga & Ultraman Dyna: Warriors of the Star of Light.