The Sol Empire is a political body that appears in the Sonic the Hedgehog comic book series and its spin-offs published by IDW Publishing. It is a kingdom ruled by princess Blaze the Cat in her own dimension.
Out of the Blue
One day, after Blaze and Gardon went over the evening report, an unconscious Sonic crash-landed near the Sol Empire's Imperial Palace, where he was discovered by Blaze and Gardon. Afterward, Sonic received a bit of rest in the Imperial Palace, but discovered that he had lost his memory. Blaze tried to remind Sonic of who he was during some tea in the courtyard, but to no avail. Not long after, Sonic returned to the Imperial Palace after having a jog around the island. In the meantime, Gardon brought Blaze the Sol Emeralds, which she used to restore Sonic's memories and send him back to his world.