Millions of years ago, Gatanozoa exterminated the ancient humans and spread darkness. Eventually, Gatanozoa and his followers, the Zoiger, retreated into the ancient city of R'lyeh to hibernate, marking the end of the age of darkness.
In modern times, Gatanozoa awoke, seeking to plunge the world into darkness once more. Standing in his way was Ultraman Tiga, occupying the human Daigo.
Summoning his courage for the entire human race, Daigo/Tiga went to fight the dark god. However, as he only had Daigo's light to power him, Tiga was unable to defeat Gatanozoa, who turned him into a stone statue that plummeted to the depths of the Pacific Ocean.
However, Tiga was revived thanks to humanity's hope pouring into his color timer. The Ultra then went to battle Gatanozoa, managing to defeat the dark god with a combination of his Glitter Bomber, the Glitter Zeppelion Ray and Color Timer Flash.
Ultraman Tiga: The Final Odyssey
When Kamila discovered that Tiga had fallen in love with another woman, Gatanozoa's hatred and anger towards Tiga transferred to her and the other two Dark Giants. Kamila later used the dark energy of Gatanozoa to transform into her final form, Demonozour.