Sega is a software developer and publisher, arcade hardware developer, and former console hardware developer. It was created through the merger of Service Games and Rosen Enterprises in 1965. Sega is the current owner of the Puyo Puyo series.
While Sega did not fully develop a Puyo Puyo game until Minna de Puyo Puyo, they have arguably played a key role in the Puyo Puyo series from the start. The arcade version of the first Puyo Puyo title was published by Sega and developed for their System C2 hardware. Additionally, they published every Game Gear title from the Puyo Puyo and Madou Monogatari series until the release of Puyo Puyo Tsu. In 1998, Sega gained the rights to Puyo Puyo and its characters after financial troubles forced Compile to attempt a restructure. Compile continued to create Puyo Puyo and even Madou Monogatari games until Puyo Puyo Box; Sega is credited in each of these games.
While Sega owns the Puyo Puyo series, they do not own the Madou Monogatari series; these rights appear to belong to D4 Enterprise. However, Sega is credited in every re-release of the early Madou Monogatari games, as the games contain Puyo Puyo characters.