He is based on the Cthulhu Mythos villain Ghatanothoa.
History
Ultraman Tiga
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.
Ultraman Orb Chronicle
Although Gatanozoa has long dead, Maga-Orochi managed to create a King Demon Beast replica of the kaiju while siphoning with Earth's elements called Maga-Tanothor. Its kaiju card was featured in "Beware of Fire in the Midsummer Sky".
As revealed in Chapter 4 of Ultraman Orb Chronicle, mirroring the original's fate, Maga-Gatanothor was defeated by Ultraman Tiga after a difficult fight near Ishtal Civlization. Rather than destroying it, Tiga resorted to seal it due to its presence, alongside the rest of King Demon Beasts at that time, cannot kill it without further ravaging the planet. Its presence inspired the foundation of the cult Magacism dedicated to worship the King Demon Beast. Under the guise of Nuru Ra Hotep, Juggler seized control over the cult and preached inhabitants of Ishtal about their impending doom before releasing Maga-Gatanothor with use of Dodongo's Kaiju Card fashioned from the monster of the same name Orb defeated earlier in conjunction of Dark Ring. Maga-Tanothor soon fight Ultraman Orb as soon as it started to wreak havoc upon buildings of Ishtal. Their fight was so intense that the heat they released during the fight turned nearby sand to glass. Although Ultraman Orb emerged victorious with Gai harvested the lingering light of Ultraman Tiga on Maga-Tanothor's remains, their battle has reduced Isthal into a place known as Kemati Buki (Hill of Death), leading to the theory of an ancient superscience war scientists thought of 4,000 years later. Shedding away his disguise, Juggler collected Maga-Tanothor's Kaiju Card where he would use it alongside the rest of King Demon Beasts' cards to unleash the Great King Demon Beast: Maga-Orochi.
