Sonic the Hedgehog is the main protagonist of the titular series.
Not much is known about Sonic's early life. All that is known is that Sonic was born on Christmas Island, and that he has spent his life traveling the world while searching for adventure.
At some point in his life Sonic met Dr. Ivo Robotnik and they became enemies under unknown circumstances. Since meeting with each other, Sonic fought Dr. Robotnik in an untold number of confrontations as the mad scientist attempted time and time again to conquer the world, with Sonic each time emerging victorious and foiling the doctor's plans. Despite their many battles, however, Sonic did not really account of his adversary.
Sonic the Hedgehog 1Edit
In Sonic the Hedgehog, Sonic heard news about Robotnik invading South Island after the doctor had discovered that powerful relics, called the "Chaos Emeralds", were hidden on the island and sought them to use their power to produce weapons of mass destruction. Annoyed by Robotnik's perseverance, Sonic hurried to South Island to stop him. Once Sonic arrived, he was met by Robotnik who revealed his new method to enslave the animal residents: by trapping them inside robotic shells, he could turn them into Badniks that would then follow his every command, a method that left Sonic greatly shocked.
Despite having the whole island as his enemy, Sonic resolved to save the animals and get the Chaos Emeralds before Dr. Robotnik could get his hands on them. After traveling across the island while freeing the animal residents and securing the Chaos Emeralds, Sonic entered the doctor's stronghold on the island, defeated the mad scientist, and managed to drive him off the island. With Robotnik defeated, Sonic reunited with his friends in Green Hill Zone, where he released the Chaos Emeralds, with their power ensured the island's prosperity. After this adventure, Sonic became a well-known hero throughout the world.