Is Hiro a Mary Sue?
He's a superior genius who is liked and admired by everybody while acting like a brat, always win, always right even when he's wrong and has justification for it.
He invented impossible technology seemingly operates using infinite energy source that envied by all people. Singlehandedly. Before puberty.
Has a friendly robot companion given to him for free and even able to modify it into his liking when he had no prior knowledge of, nor any meaningful training, also surrounded by friends that always look highly of him even when he's actually the weakest (okay, second weakest) hero while being the only one who can defeat the villain and saves everyone.
He's like a fan-fic character written by teenager robotic nerd who has no friends. Is he not?