The Fate Revolution Circuit system is designed to drain the power of God from Disgaea 4: A Promise Unforgotten
The Multiverse is filled with positive and negative energy. Yin and Yang. Sometimes, too much demonic energy comes together to form the Superboss from the Disgaea series; Baal. In Disgaea 4: A Promise Unforgotten; God is not a high school student who won a raffle. (We think), it's a super-powerful; unforgiving force like in the Shin Megami Tensei series. Here we have the opposite of Baal; a force of light that grew too strong. The Creator is an entity who can manipulate celestial and demonic energy and give it to certain beings; but once he does; he can't control what they do. Like Satanael; Disgaea 4: A Promise Unforgotten's God was a "whoops" too much energy; in this case celestial.- Originally, many "Black Wings" were created by the Creator to counter this God. However, most were not interested in doing so and targeted humanity instead. A more subtle; balanced plan was needed. Many, many humans were given the power of God to drain the Mega-God's celestial energy; and then they were thrown at whatever Black Wing or Demon Overlord was the biggest problem. Most died; but this fulfilled the requirement of "using up" the fraction of celestial God energy. Whenever a "God pro tem" succeeds, usually he dies as a result of losing that energy anyways. Then the White Wings move base to another part of The Multiverse where there are more Black Wings and they can throw more human God pro-tems at them in the unending "Final War between Angels and Demons."
The "Creator" Renya meets is literally a Creator Cameo (of sorts)
Yes, the Creator is a Demiurge-style Jerkass with Orange And Blue Morality, but if you read all of his dialogue as if he were aware of the Fourth Wall, then he's right: all that distinguishes angels and demons, in his mind, is their color palette, and he finds their war amusing. He also challenges Renya (the player) to defeat his "strongest creation" (not counting the Superboss, Satanael is pretty much the toughest fight in the game).