In the first of the [[Number ruins|ruins]], Yuma obtained the first Mythyrian "Number", "[[Number 44: Sky Pegasus]]", from [[Mach]].
Next, "[[Number 96: Dark Mist (character)|Dark MistNumber 96 ]]" acquired the second Mythyrian "Number", "[[Number 65: Djinn Buster]]" from [[Battle Ox (character)|Battle Ox]].
After that, Alito acquired the third Mythyrian "Number", "[[Number 54: Lion Heart]]" from [[Number 54's guardian]], but gave it to [[Nistro]] so he could control him. After they lost the Tag Duel, Nistro gave Yuma the "Number".
When the [[Different Dimension Airship]] crashed at sea, Rio was called to the bottom of the sea by the guardian [[Abyss]]. Following her along with [[Yuma Tsukumo|Yuma]] and [[Astral]], [[Reginald Kastle|Shark]] eventually defeated Abyss' "[[Number 73: Abyss Splash]]" after being shown memories from his past life, using the ruins' second Mythyrian "Number", "[[Number 94: Crystal Zero]]", putting most of the Mythyrian "Numbers" into the possession of Yuma and his allies.
Yuma and Astral defeated Number 96: Dark Mist at the cost of Astral sacrificing himself to protect Yuma from a fatal attack, leaving Number 65's in Vector's control due to his absorption of the Forbidden Number's sealed form after his return to its progenitor - Don Thousand.
If these cards or their corresponding Number C's clash with the corresponding "[[Number 10X]]" (or "[[Number C10X]]") they awaken the original memories of the legendary figure described in the ruins. This also causes any malignant influence from Don Thousand to disappear from the respective Emperor.