In sonic 2, Knuckles and Robotnik hunt down the Master Emerald, a green diamond that is too powerful for anyone to wield. Whilst getting to it, Sonic fights Knuckles and Robotnik betrays Knuckles and takes the emerald. So, knuckles teams up with sonic and tails and they defeat Robotnik. After his defeat, a military gotten coordinates to something. PROJECT SHADOW

make your own character or be Shadow