Sega Corporation (株式会社セガ, Kabushiki-kaisha Sega), officially stylized as SEGA, is a multinational video game software and hardware development company, and a home computer and former console manufacturer headquartered in Ōta, Tokyo, Japan, with various offices around the world. The company is famous for many notable game franchises, including Sonic, Bayonetta, Virtua Fighter, Jet Set Radio, Crazy Taxi, Alex Kidd, Puyo Puyo, Phantasy Star, Shenmue, Yakuza, and Valkyria Chronicles. In the past, Sega was Nintendo's greatest rival. They even made anti-Nintendo campaigns, such as the old American marketing slogan for the Sega Mega Drive (Sega Genesis in North America), which was "Genesis does what Nintendon't". The company had success with both arcades and home consoles, but on January 31, 2001, following poor sales of the Dreamcast and profit losses, Sega restructured itself and left the consumer console business to concentrate on software development for multiple third-party platforms. Since then the company has made frequent collaborations with their former rival, including releasing exclusive games for their consoles and occasionally developing games involving their IPs, such as F-Zero GX, F-Zero AX and the Mario & Sonic crossover sports series. On October 1st, 2004, they merged with a Japanese pachinko company called Sammy to form Sega Sammy Holdings, but still exist as a subsidiary of the company. The company is also famous for its SEGA! chant that appeared on both commercials and games. On September 2013, Sega Sammy Holdings acquired Atlus, obtaining the publishing rights for franchises such as the Megami Tensei series and its various subseries such as Persona.
Sega was described as being in "special collaboration" with Nintendo regarding Sonic's inclusion in Brawl, where he and Solid Snake became the first third-party characters to appear in the series. Additionally, other characters from the Sonic franchise, such as Shadow, Tails, Knuckles, and Silver, have minor roles in Brawl, and the iconic Sonic level, Green Hill Zone, appears as a stage. Content from F-Zero GX also makes its Super Smash Bros. debut in this game in the form of music, stickers and updated designs of featured F-Zero characters.
Sega's mascot Sonic returns as a third-party character in Super Smash Bros. 4. Additionally, Windy Hill Zone, a stage from their Nintendo (3DS/Wii U) exclusive Sonic Lost World, appears in Super Smash Bros. for Wii U, while Green Hill Zone returns from Brawl in Super Smash Bros. for Nintendo 3DS. Two Mii Brawler costumes based on Akira Yuki and Jacky Bryant from Sega's Virtua Fighter series appear as downloadable content. In addition, Mii costumes based off Knuckles and Tails appear for the Mii Brawlers and the Mii Gunners, respectively. Bayonetta from the Bayonetta series is another newcomer, available as DLC. She is Sega's second playable representative in Super Smash Bros.
Both Sonic and Bayonetta return as third-party playable characters. In addition, the Green Hill Zone stage returns from Brawl and 3DS as well as the Windy Hill Zone stage from Wii U and the Umbra Clock Tower stage from 3DS/Wii U. Shadow returns as an assist trophy. Knuckles, Rodin and Akira Yuki also debut as new assist trophies. Akira and Jacky Bryant also return as Mii Brawler costumes. Joker from Persona 5, developed and published by Sega's subsidiary Atlus, makes an appearance as a DLC character.