The Sonic the Hedgehog franchise has an incredible cast of characters within the video games and spinoffs. Although a video game character may have appeared in the comics, it was less likely to see a character originating from the comics in one of Sonic's mainline games. With such an ensemble cast, it would be obvious that so many of them have interesting backstories. Because of this, it's easier to narrow down which Sonic character has the stronger backstory by only looking at the cast of video game characters and exclude the spinoffs/non-mainline canon.