Classic Sonic

Sonic Generations (2011)
Probably somewhere after the events of Sonic the Hedgehog 3 & Knuckles, Sonic is kidnapped by some dark entity from his dimension and finds himself in some white room. He explores the area and finds places he recently visited, as well as many unfamiliar places. Soon, Sonic, to his surprise, encounters himself from the future. Sonic fights Dr. Robotnik, who attacks Sonic with a good old Death Egg Bot and wins, but then Robotnik is kidnapped by the same dark entity as before. Sonic finally gets to know his version from the future. It turns out that along with Sonic from the past, Tails from the past is also in this world, as well as many of Sonic’s friends from the future. Together, the two Sonics rescue their friends and collect the 7 Chaos Emeralds, finally meeting the dark entity in battle. It turns out that it’s named Time Eater and is controlled by Dr. Eggman along with his version from the past, Dr. Robotnik. Using the Chaos Emeralds, the Sonics take the form of Super Sonics and defeat the evil Doctors, after which all the heroes return to their own time.

Sonic Mania (2017)
Dr. Robotnik finds a mysterious artifact capable of changing reality through illusion – the Phantom Ruby. With this mighty artifact, Robotnik strengthens his Egg-Robos into Hard Boiled Heavies and creates a mighty army of giant robots. Sonic, with Tails and Knuckles’ help, defeats Robotnik in battle. However, one of the Egg-Robos, the leader of Hard Boiled Heavies, Heavy King, has gained intelligence thanks to the Phantom Ruby and steals the Ruby. Sonic, using the 7 Chaos Emeralds, becomes Super Sonic and fights Dr. Robotnik and the Heavy King for the right to possess the Ruby. Super Sonic wins the battle, but the Phantom Ruby suddenly opens a portal when it comes in contact with the Chaos Emeralds, pulling Sonic into it.

Sonic Forces (2017)
Sonic comes out of the portal just in time to save Tails from Chaos attacking him. As it turns out, Sonic has traveled to a parallel dimension inhabited by the same Sonic from the future that they worked with in Sonic Generations (2011). Tails reveals that the Sonic from this dimension was captured by Eggman with the help of the Phantom Ruby and the new villain using it, Infinite. Without Sonic in the picture, Eggman has managed to take over 99% of the world and only weak parts of The Resistance are still fighting. With Tails, Sonic sets out to explore the devastated world, battles Eggman and his robots and finally joins The Resistance, which has already freed Sonic from captivity and is preparing a plan of a counterattack. Both Sonics, with considerable help from the Resistance’s newcomer, Avatar, defeat Eggman and Infinite. During the course of the adventure, Classic Sonic formed a very friendly relationship with Tails from the future and before returning to his dimension, they had a very hard time saying goodbye.

Sonic Mania Plus (2018)
Back in his dimension with the Phantom Ruby, Sonic finds the captive pods of Mighty the Armadillo and Ray the Flying Squirrel. After freeing them from the capsule, Sonic lets his guard down and allows the Hard Boiled Heavies’ surviving robot, the Heavy Magician, to catch him vulnerable, resulting in the Heavy Magician taking possession of the Phantom Ruby. Using the artifact, Heavy Magician recovers the Hard Boiled Heavies and teams up with Dr. Robotnik in another battle with Sonic. Sonic, Mighty, Ray, Tails and Knuckles work together to find all 7 Chaos Emeralds to fight the villains and win, but the tense battle results in an unstable opening of a huge portal by the Phantom Ruby. Using their Super forms, the heroes manage to escape while Robotnik is pulled into the unknown by the portal.