This story is based on two central ideas:
1. Chimera is a mythical beast in Greek mythology with the head of a lion, the body of a sheep, and the tail of a snake. Scientists call the phenomenon that normal people carry at least four sets of DNA, that is, twins born as chimeras [not conjoined twins, but the genes of one fetus absorbed by the other fetus], called the Chimera phenomenon.
2. Some people say that twins are a complete person split into two whole people. They can always complement each other. Because there are no perfect people in this world, it is assumed here that they can achieve perfection by complementing each other.
Finally, I would like to thank mothy's Seven Deadly Sins series of the V family and ATOLS's "Chimera" (feat. IA) for opening up my imagination. The story partially refers to and pays homage to the works of the two great gods [so it is a bit funny x], and I refuse to plagiarize.
References: Gemini setting, original sin story part, the meaning of Chimera
No CP... At least there is no love between the protagonists