The oldest Mikogami sister, and the most mature. A typical middle school student, Nagisa is a shy, quiet girl. She can transform into a dog with the help of a locket, often partaking on misadventures with her little sisters Riko and Rimu when transformed. She cares a lot for her sisters. This can be seen especially when Riku and Rimu do something dangerous. She has a crush on Ryuudou Pulse.