After defeating Eggman for good, Sonic and Tails rush with the Master Emerald to raise Angel Island back to its place in the sky. However, parts of the Giant Eggman Robo rain down on the island, causing havoc for the residents there

Knuckles, who was on the island, is killed by debris of the robot landing directly on top of him. Sonic and Tails watch on in horror as parts of the island catches on fire due to Eggman's creation.

A fierce argument breaks out between the two on how Sonic wasn't quick enough to save the island. In their anger, they fail to see the final scraps of metal from the robot clash against the plane. Both crash into the island and die on the spot.

But in spite of that, the lingering power of a now shattered Master Emerald revives Sonic from death. Although in less then desirable conditions. His body is beyond tattered, and his soul is filled with nothing but regret. With Knuckle's death and Tails's final words of hatred dwelling deep in his heart.

He wonders around the island, seeing the inferno and carnage for himself until he comes across an out of commission Mecha Sonic. Reaching his hand out to him, it bolts back to life now directly under his control.

While his body is in poor shape, the power of the Master Emerald has allowed him to possess things and create portals between new realms. Allowing him to go wherever he needs to be.

Mecha Sonic now serves his new master just as faithfully as his old one. An emotionless machine that will take any order with no questions to keep them safe. He now covers for Sonic's stunted physical power and speed.

In his hubris, Sonic concludes that this new hell he is in was caused solely by Eggman. He wishes nothing more then to scrub all places from things like him, so that others may not meet the same fate.

He sees humans now as nothing more then selfish creatures that only care for their survival, willing to destroy all should they not have their way. Even in death.

He hunts humans using his portals, taking great joy in killing those he finds particularly irredeemable. Seeing himself above those sacks of meat and delivering his own idealized version of true justice.

Despite that, no amount of bodies can ever fill up the bottomless void of regret in his heart. No matter how much he tries to hide it, it eats away at his mind. He desires that same warmth he once had, but he fears losing it all over again.

His quest allows him no means to find that love which once made him a great hero, and that... is his curse.