Sega Technical Institute
From Sega Retro
STI was at one time an elite organization within Sega of America that developed well-received games such as Die Hard Arcade (the result of a team-up between STI and successful arcade game developers AM1), Comix Zone, Kid Chameleon and The Ooze. STI's focus was to create character properties that could be built into a franchise.
Though the original Sonic the Hedgehog was developed in Japan, Sonic Team moved to the STI headquarters for the development of Sonic the Hedgehog 2, and several STI members assisted in the development of that game. Sonic Team stayed for Sonic the Hedgehog 3 and Sonic & Knuckles but did not seek help from STI for the development of those games.