Subterranean Monster Appears! And Appears!

The Sasamedake flower blooms. It is said to be the harbinger of disaster! Then, a golden rainbow appears in the sky! As if responding to its call, a subterranean monster appears! Ryumon is injured as this unprecedented situation unfolds. Kanata tries to cheer him up, but....what lies at the end of Ryumon's gaze?