is a Japanese national and former Sega employee who designed the characters of Sonic the Hedgehog and Doctor Ivo Robotnik (Doctor Eggman). However, Yuji Naka often gets the credit for his work on the Sonic series, because of his close association with the Sonic name. Ōshima gained renown at Sega's Sonic Team for creating characters and playing integral roles in the development of games like Phantasy Star, Sonic CD, Nights into Dreams..., and Sonic Adventure.

After leaving Sonic Team, he formed an independent game company called Artoon, of which he is currently president. There he went on to work on such games as Pinobee and Blinx: The Time Sweeper, and in 2004, the sequel to Blinx, Blinx 2: Masters of Time & Space.

He is occasionally credited under the nickname "Big Island", which is a literal translation of his family name.

Production history

• Phantasy Star (1988) — Design
• Phantasy Star II (1989) — Design
• Sonic the Hedgehog (1991) — Character Design
• Fatal Labyrinth (1991) — Designer
• Sonic Eraser (1991) — Special Thanks
• Sonic CD (1993)— Director
• Knuckles' Chaotix (1995) — Original Character Concept
• Hyper Athlete (1996) — 3D Background, Camera Work
• Sonic 3D Blast (1996) — Advisor
• Nights into Dreams... (1996) — Director, Visual Designer, Character Designer
• Sonic R (1997) — Graphic Advisor
• Sonic Jam (1997) — Supervisor
• Burning Rangers (1998) — Director
• Sonic Adventure (1999) — CG Movie Producer
• Silent Hill (1999) — Effect Programmer
• Kessen (2000) — Special Thanks, Sound
• Pinobee: Wings of Adventure (2001) — Director
• Blinx: The Time Sweeper (2002) — Director
• Silent Hill 3 (2003) — Effect Programmer
• Blinx 2: Masters of Time & Space (2004) — Director
• Yoshi's Island DS (2006) — Producer
• Away ~Tsuresarareta Hitobito~ (2008) — Character Designer