Well, with Sonic and the Secret Rings, the One-Thousand and One Nights stories it's based on are middle eastern folktales, so probably where those two got their names from (Ifrit, Arm of Iblis: demon, arm of Satan). With Sonic the Hedgehog (2006)'s Iblis, what better name for the bringer of the end of the world than Satan? And for Sonic Rivals 2, same logic, it's a demon that brought about the end of the world. Yet people put Sonic the Hedgehog CD between Sonic the Hedgehog 2 and Sonic the Hedgehog 3. Either way, people think there's events between Sonic the Hedgehog 2 and Sonic the Hedgehog 3, so why is it so terrible I have events between them as well? We don't know how long the Death Egg took to fall, so a couple of months with some smaller adventures in-between is hardly continuity breaking.