He is the prime minister of Japan and wants to develop and privatize it just like his real life counter part. He's trying to buy the daikon farm via his two henchmen, Yuukel Hakushon and Donabenabe, so he can build a parking lot among other things in its place. When his men fail to obtain it via diplomatic means, he tries to take the farm by military force. He is a parody of the real life Japanese politician Junichiro Koizumi.
Oizumi likes to sing and travels around in a giant flying city hall with his secretaries who repeat everything he says but whom can also fight for him while wearing lion costumes.