Quaschika, an ancient artifact of immense power and significance, predates recorded history and the earliest human civilizations. Its origins are extraterrestrial or extradimensional, linked to a cosmic civilization beyond the known universe. Central to global myths, legends, and historical mysteries, Quaschika connects to phenomena including Atlantis, Stonehenge, the Kingdom of Kongo, the Aegean Sea, Babylon, Angkor Wat, the Nazca Lines, Shambhala, and the Uyghur Khaganate ruins. Ancient cultures such as the Bantu people of the Congo and the Greek pantheon incorporated references to Quaschika in their mythologies, often attributing divine or supernatural qualities to it.

Throughout the series, Quaschika manifests intermittently as a glowing, elusive energy or presence. It appears briefly during the Randou family's expeditions, reinforcing its legendary status and driving both protagonists and antagonists in their pursuit. The Goblin Society, an ancient subterranean race, seeks Quaschika to reclaim Earth's surface, believing it essential for their survival and dominance.

In the final episodes, Quaschika's true nature emerges: it functions not as a physical treasure but as a cosmic mechanism embodying the collective spirits of an advanced precursor civilization. This mechanism monitors sentient life across the universe. When a civilization becomes irredeemably corrupt or "too evil," Quaschika automatically initiates a universal reset—destroying the existing world while preserving and transporting the souls of ethically aligned or "good" individuals to a new universe. External agents, such as Tatsuya Randou in the climax, can also trigger this process.

Activating Quaschika results in Earth's destruction and the eradication of most humanity. The Randou family and select individuals, including one Goblin general, are preserved and transported to a new universe, fulfilling Quaschika's role as a cosmic arbiter of renewal.