World Illusion

World Illusion  (Japanese: ワールドイリューシン Wārudo Iryūjon) is an incident that happened in Yu-Gi-Oh! ARC-V (manga). World Illusion is a phenomenon resulted from a part of Genesis Omega Dragon's (G.O.D) power that Yūshō Sakaki used to prevent the world from destruction.

When the world was about to be destroyed by G.O.D's power after Leo used Real Solid Vision to materialize its power, Yūshō stole the card and used a part of this power to regress time to more than 20 decades in the past as the last ditch of effort to stop the whole world from being destroyed. Consequently, the phenomenon also caused the future timeline where Yūya Sakaki and Reiji Akaba, the only two survivors of the incident, originally came from to cease from existence.

Due to yet unknown reason, the impact of World Illusion somehow caused the spirits of Yūya's older brothers, Yūto, Yūri, and Yūgo, who were supposed to have perished together with their timeline, to survive and keep on living inside Yūya. The impact also caused Yūya to partially lose his memories, making him forgot about his brothers and several things about himself.