Forbidden Gods

The Forbidden Gods (禁断邪神) are an antagonistic faction of gods that are a looming threat across the Mahou Kaiju Series, only becoming an active threat in the series' Kaiju World War Arc. Extremely powerful, unique and malignant beings of great and immense power, they are horrific deities who spread chaos, death and destruction across the universe and rule over the Forbidden Ones, existences that are beyond comprehension of regular living beings in Earth, as well as many worlds outside.

They are a pantheon of demonic extraterrestrial gods that are more known amongst mortals than the Final Gods but are infinitely less powerful. Regardless of this fact, the Forbidden Gods are completely invincible in comparison to even the regular gods (such as the Greek, Egyptian and Norse gods) and their alien nature is so utterly bizarre to humanity that it inspires madness in all who gaze upon them, even with the existence of kaiju, gods, the Magi and other extra-human forces being already known to the common eye.

The Ancient War
Several millions or even billions of years in past, the Forbidden Gods were at war with the Ancient Gods, another pantheon of powerful entities who maintain peace and order in the cosmos. Across several eons, many Ancient and Forbidden Gods were killed in the long conflict that ended with all of the remaining ones sealed by the Ancient Gods, with a lot buried beneath the sea, other inside the Earth, and still others in distant planetary systems (and beyond).

It is believed that the Forbidden Gods are intentionally quiescent. To account for this, it is possible that the universe experiences cosmic cycles, similar to the seasons of the earth. Just as some animals hibernate during the winter, so too must the Forbidden Gods rest in death-like sleep during the present cosmic cycle. If this is so, the Forbidden Gods are currently trapped by powerful cosmic forces and must remain so until such time as "the stars are right"; the event whenupon they are released and can revel once more across the cosmos.

Behavior
Cataclysmic and malevolent, the Forbidden Gods have the power to end the world, or even perhaps an entire galaxy, on a whim but don't actively seek the destruction of various living species, perhaps it is due to their vast power, because to them, mortals are not worth the trouble of extermination. However, with the threat of humanity's power in light of many wars against the Underworld and even gods, Earth soon finds itself at war with the terrifying gods of the unknown.

Normally, a Forbidden God would simply choose to destroy entire civilizations for no other reason than it felt like it, it has no care if its actions cause the deaths of thousands, and if a Forbidden God should become hungry or bored, it sees no wrong in randomly murdering, torturing or devouring innocents.

Trivia

 * The overall nature of the Forbidden Gods are an homage to the various group of deities from the Cthulhu Mythos in the works of H.P. Lovecraft, Brian Lumley, and the Call of Cthulhu RPG, in particular the Great Old Ones.