Does that mean there will be seven characters that will have chaos emerald?
Including Sonic, Tails, and Knuckles?
(Oops, ment to post this in the Sega Movie thread.) But yeah that's my theory. My guess in the next movie (or the very least ending teaser) Amy Rose will be introduce who has the power of the pink/purple Chaos Emerald.
A fantheory of mine is that at one point Longclaw tried to steal this power from the Echidnas but before she could get away with it she lost the power and a seventh of this power ended up in a baby hedgehog, turning it blue. She stole the baby to raise for herself in hopes to take back the power from him, though maybe ended up caring for him.
That's why the echidnas in the first movie attacked them, they were not after Sonic, they were after Longclaw for stealing the power.
At least that's my theory. I bet Longclaw survived the attack from the Echidnas (no confirmed kill after all) and found Tails who possessed the yellow chaos power which grants him flight. Thus she got Tails to look for Sonic.
I bet Knuckles possess red energy which gives him enhanced strength. And that the green crystal that Dr. Robotnik found is the Master Emerald.
My guess if there will be Super Sonic, either his friends will lend him their power, or the Master Emerald will draw the power from Sonic and his friends and crystalize that power into Chaos Emeralds.