Sega is an organization of terrorists who frequently try to destroy Nintendo, Nintendon't and Nintend'oh. They occasionally make their own video games to rival Nintendo's. They have shared a violent rivalry with Nintendo since the video game war. Despite Sonic's success in the Video Game War, their game sales are very poor and they are likely to go into bankruptcy soon.
Sega comes from "seja", which is Spanish for "dangerous criminal."
Sega was originally a gangster club in Seattle. They stole many items from museums, stores, and restaurants. And one day, someone stole all their money, treasures, jewels and even a Chaos Emerald. They had to think of a way to get more money. And that was by starting a video game company which they thought would earn as much as Nintendo gets. So they founded Sega corporation.
Soon, Nintendo's sales began to go down as Sega's went up. It was then that Sega hatched a plan to destroy Nintendo and all other video game companies, making them the lat one standing. Nintendo and Sega have had a violent rivalry ever since. And their plan has almost worked but they were always foiled. However they have a new mascot called "Black Thing", and they have a new plan.