Mephiles was the manifestation of the mind and will of the sun god Solaris. He was born during the Solaris Project when the experiments on Solaris split him into Mephiles and Iblis. After his birth, Mephiles was sealed inside the Scepter of Darkness by a time-traveling Shadow the Hedgehog, but was accidentally freed a decade later during a skirmish between Shadow, Rouge the Bat, and Doctor Eggman. (Source: Sonic Wiki Zone)