The Guardian of the Stone is a character in the series.
The Guardian of the Stone is a robot resembling Sonic. It is similiar to the Giant Mecha Sonics, but it's doesn't side with Cain's organization. It protects the Stone.
Episode 3 Edit
After completing the puzzle at the end of Episode 2, Sonic sees the room go dark and his friends disappear. The only light remaining is from the Guardian of the Stone. The lights turn on and the robot attacks Sonic, starting a fight. Sonic, after winning the fight and destroying the robot, obtains the Stone it was guarding. After this the room goes dark again, only to light up once more, returning Sonic to his friends.
- It might resemble Sonic because he is the chosen one to get the Stone.