Board Thread:General Discussion/@comment-1031724-20160828014723/@comment-28049558-20160902222756

I think that there's basically a Multiverse, the 'main series' and the Storybook games appear on the Sonic equivalent of Earth-1 (with Sonic 06 being negated). Sonic Boom appears in a separate universe - Earth-2. Sonic Chronicles is Earth-3, Mario and Sonic Earth-4 etc.