"BRAVE UP! J-DECKER!"
-Yuuta issues the unification command, "The Name Is J-Decker"
Yuuta Tomonaga (友永勇太 Tomonaga Yuuta) is a fourth grader who accidentally came in contact with the robot Deckard during his testing stage. Through this contact with Yuuta, Deckard gained a heart and the two became fast friends. Eventually, Yuuta was inducted into a special division of the police force by Juzo Saejima called the Brave Police. Affectionately called 'Boss' by all under his command, he is kind and willing to help anyone in need. Yuuta is a bit naive at times, but he can make good judgements when it is needed.
Yuuta is a young boy with unruly dark blue hair and blue eyes, like his father. As the leader of the Brave Police, he is determined and optimistic, though he can be emotional and impulsive at times. He is fiercely loyal to Deckard, refusing to abandon his friend even if it puts him in danger.
Yuuta first met Deckard six months before the start of the series. He had been out flying an remote-controlled plane when it crashed into the ground near a tunnel that lead to Deckard's underground bunker. Yuuta slipped and fell into the tunnel, where he crash-landed in the bunker and accidentally awoke Deckard, who was still being built. The robot introduced himself to Yuuta, who in turn told him his name. Those were the first words imprinted on Deckard's memory. After that, Yuuta would come and spend time with Deckard, teaching him how to walk, introduce himself, and reading to him. He also helped Deckard gain a heart and understand emotions like joy, anger and sadness. ("Introducing the Robot Detective")
- In previous drafts of the show, Yuuta was a girl. Much of those features were kept, and in one episode he ends up wearing a dress and pigtails. It is speculated that any gender confusion this caused was intentional.
- So far, all of Yuuta's clothing has a music note motif somewhere on it.