Gameru is a ninja who possesses one of Iou's prototype ninja tools, Dako. Him along with Kusune came to Iou to get ninja tools but he refused to give some to outsiders. Gameru and Kusune fight Naruto Uzumaki and Neji Hyūga who are no match against Iou's ninja tools. When Iou gives Tenten his latest invention, Jidanda, Tenten easily defeats the two.

(source: Narutopedia)