Talk:Head Researcher/@comment-45230802-20200516122659/@comment-43917081-20200820041814

“Hey Kazuma, the time flow in Japan, heaven and this world are all different. For example, one month in Japan’s just an hour in heaven, but is several months in this world. And so, my age… Hey, are you listening?”

From volume 5. Since the Head Resarcher explicitly uses 80s-90s games, this matches up reasonable well. (~30 years before Kazuma in Earth time,  so 100-200 years Konosuba time)