Board Thread:Sonic News and Updates/@comment-24108393-20131118164338/@comment-679780-20131209054849

S&tSR and S&tBK are set in alternate dimensions and regarded as spin-off's as while the characters looks exactly like Sonic's friends, they're actually counterparts native to those worlds.

The crucial thing that ties these spin-off's to the canon is the fact Sonic himself visits these worlds. Shahra brought Sonic to Arabia through the book. However, in S&tBK, a book is never really shown and Merlina merely summons Sonic to Grand Kingdom through a portal.