Arimura Nozomi- Wakui Mito - The Virile Old Man... 90%

Coming [Month/Year] "Age is not a number. It's a weapon."

Since I don't have direct access to an officially published work with this exact title (it may be a niche doujinshi, a fan translation, or an upcoming series), I will draft a based on the archetypes and keywords you provided. You can adapt this to the specific plot you have in mind. Arimura Nozomi- Wakui Mito - The Virile Old Man...

Arimura Nozomi lives by the book. As a junior analyst in a Tokyo security firm, she believes data, rules, and procedure are the only paths to success. Wakui Mito, a cynical street-smart courier, believes the opposite: rules are cages, and only the ruthless survive. They have nothing in common—until a botched corporate heist traps them both in an abandoned subway tunnel. Coming [Month/Year] "Age is not a number

Their savior? A grizzled, 78-year-old retired construction foreman with thick wrists, a booming laugh, and a presence that fills a room. They call him the Oni no Jiji (Demon Gramps). Arimura Nozomi lives by the book

When a younger antagonist mocks him ("Shouldn't you be in a home, grandpa?"), the old man doesn't fight. He simply picks up a 50kg cement bag one-handed, tosses it to the man, and says, "Catch. If you drop it, you're buying dinner." The man crumples. The old man doesn't laugh—he helps him up. That is virility. Option 4: Short Promotional Blurb (Social Media / Ad) They thought he was a relic. They were wrong.