Katsura Kusunoki's "Onikiri Maruden" latest volume 21. A suspicious dead head flying in the mountains ... What is the tragedy told by the monster enshrined by the mountain god (spoilers ahead)

Katsura Kusunoki's "Onikiri Maruden" latest volume 21. A suspicious dead head flying in the mountains ... What is the tragedy told by the monster enshrined by the mountain god (spoilers ahead)
The latest 21 volumes of the manga "Onikiri Maruden" will be released on November 26th....

The linked article is in Japanese.