Taruru

Taruru used to be Tamamas apprentice and still calls him quotmasterquot or quotsenpaiquot meaning his superior Taruru was more clumsy than Tamama in the past. Taruru was a blue Keronian tadpole whos symbol is an orange and yellow raindrop shaped emblem the mark of an quotold driverquot in Japan but he matured faster in his appearance in volume 10/episode 101 he had adult features instead of tadpole features. Taruru first appeared to see if all the rumors about the Keroro Platoon was true revealing what Tamama told him about the platoon. In the anime he also appeared a couple of times with his childhood friend Karara forming a duo of mischievous tadpoles. Despite Tarurus clumsiness in the past he had become very skilled when training in the Garuru Platoon and has skills that exceeded Tamamas defeating him in a faceoff. He then captures Momoka and Paul then later on also captures Mois. After Keroro encourages his platoon to rise Tamama after receiving power from the Super Rhinocerous Beetle returns for a rematch and Taruru is defeated. Source Wikipedia