Sonic The Hedgehog

Ten years before the events of Nagisa Shiota: Spider Assassin lives a tale about Sonic, the world's fastest hedgehog and fastest thing alive, who's having the time of his life after his long-time rival, Dr. Eggman, mysteriously disappears from his home planet, which allows Sonic and his friends to take it easy and not have to deal with his annoying schemes.

However, the fun suddenly ends when Tails, Sonic's best friend, learns that Eggman had found a way to teleport himself to a different dimension, to a planet very similar to theirs. Without Sonic there to stop him, he quickly took over and enslaved almost all of humanity. Knowing that something had to be done, Sonic and Tails break into Eggman's laboratory and find the device that he used to transport himself to this new planet.

Now, it's all up to the world's fastest hedgehog to undo everything that Eggman had caused, and without the help of Tails or his friends, it's a one-man job as Sonic has to destroy all seven Chaos Emerald Bases located around this new Earth and collect the emeralds that powered them to free the innocent humans Eggman had enslaved and conquered. Unfortunately, Eggman was nothing like he was in years prior. Sonic's day of reckoning has arrived.