Keroro Gunsou Mushakero Ohirome Sengoku Ranstar Dai Battle 6.61
Other Name: 武者ケロ お披露目！戦国ラン星大バトル！！
Summary: This was the 14-minute movie that was screened in theaters with Keroro Gunsou Movie 3. It became the prequel to the Mushakero in season 5 of the main Keroro Gunsou anime series. It takes place in Ranstar where the Keroro platoon are up against the Vipers. The whole setting of Ranstar is based on the Sengoku Era of Japan, and all characters are dressed in that fashion. A special training program will be imposed on the Keroro platoon as a punishment for failing to submit the Earth Invasion Report. It is to defeat the warrior Viper who controls the Sengoku Ran star. They want to return to life on Earth, and they will fight in armor.