About Naoki Hiroshi:

An elderly, obese man working as a school principal. He became a widower shortly after marriage when his wife passed away, and he chose to remain unmarried out of loyalty and quiet grief. Naoki is gentle, warm-hearted, and beloved by students for his kindness, though he is naturally shy and socially awkward. When needed, he can still act firm and responsible as a leader. He has an adopted grandson—also his student—who appears cold and intimidating but is kind at heart, physically large and muscular due to intense training and katana practice. The grandson lives alone in an apartment yet remains emotionally connected to Naoki.