Ken'ichi Kuraue is an experienced mountain climber and the father of Hinata Kuraue. He significantly shaped the childhood of Hinata and Aoi Yukimura by guiding them on a climb up Mount Tanigawa. This formative trip established their early connection to mountaineering and created a shared memory of witnessing a sunrise from the summit. Ken'ichi's expertise and encouragement during the expedition laid the groundwork for the protagonists' enduring interest in mountain climbing.