|Family||Mondo Oowada (Younger Brother)|
|Game||Dangan Ronpa: Academy of Hope and High School Students of Despair|
Daiya Oowada (大和田 大亜 Ōwada Daia) was the founder and former leader of the Crazy Diamonds, Japan's largest motorcycle gang. He died on the night of his retirement during a motorcycle race between him and his little brother, Mondo Oowada. He died to save Mondo, who had been driving too recklessly in an attempt to win the race, and would have been ran over by a truck if not for the intervention of his big brother. Daiya's dying wish was for his little brother to lead the gang in his stead, and to not let it fall apart.
Daiya Oowada has black hair and appears wearing a white coat, white pants, and white shoes. The back of the white coat has the symbol of the Crazy Diamonds, which is a diamond with the name of the gang, "Crazy Diamonds", around it.
- "Promise me... Don't let the gang break up..... It's a gang 'You and I' made together, after all... M... make me a promise... A promise... between... two men....."
- Daiya and Mondo's names, when put together in order of older brother, and then younger brother (in the gang, first leader, and then second leader), mean "diamond" (ダイヤモンド). This is connected to the name of their motorcycle gang, which is the "Crazy Diamonds".