Number ruins

A Number's Ruins (ナンバーズの遺跡 Nanbāzu no Iseki) are ruins where the "Legendary Number" cards are sealed, guarded by its spirits across the world in the Yu-Gi-Oh! ZEXAL anime. There were seven different locations of different Number's Ruins shown on-board the Different Dimension Airship.

Each set of ruins consist of deadly traps and inscribe a legend on its wall telling the story of the person who occupied that location in a previous era, before they became ruins due to the ravages of time. Kazuma Tsukumo had explored these ruins and left a "Conqueror's Coin" to mark his presence.

Each ruin seen so far appeared to have some sort of connection to one of the Seven Barian Emperors. Furthermore Astral confirmed that so far Durbe, Vector, Alit and Misael were humans once and that they are the same individuals described on each of the legends. Each of the ruins and Numbers appear to coincide with different periods of time: Durbe's legend associated with the Greek, Alit's associated with Roman, Vector's associated with Medieval Times and Misael's association with Chinese folklore.

Number 44's Ruins (Temple)
The temple's ruin is where one of the "Legendary Numbers" slept. On its walls, a tale is inscribed about a pegasus named Mach who served a legendary hero. The hero served a land along his fellow knights, but eventually he returned to his to home village. Without the hero, the other three knights grew arrogant and usurped the King, but were intercepted by Mach and his master. Since the hero was unwilling to kill his former comrades, both master and steed were eventually defeated and killed. However, the hero's fellow knights regretted their actions and they buried him and Mach together. Mach later became the "Number" spirit guardian of "Number 44: Sky Pegasus".

Durbe had some recollection of it as well and was able to read the ancient writings regarding the pegasus legend. Yuma Tsukumo and his friends traveled to this ruin in order to obtain the "Number". Yuma faced Mach in a Duel with Shark's and Durbe's lives at stake, and won, getting the ruin's "Number".

Number 65's Ruins (Castle)
The castle's ruins is a "Number's Ruins" where "Number 65: Judge Buster the Adjudicutting Djinn" sleeps. The ruin's prophecy, which Rio was able to read, spoke of legend about a ruthless prince, who never trusted anyone and killed his people who he believed plotted against him. When the prince was the only one left in his land, he committed suicide in atonement of his actions.

Vector and Number 96 arrived at these ruins, defeating the "Number's" guardian, Battle Ox. By acquiring the Ruin's "Number", they also gained knowledge about the Ruin's traps and how to control them. During the visit, Vector was shown to be familiar with the ruins and felt dread towards both the ruins and its "Number". When Yuma and his friends arrived, looking for the ruin's "Number", Vector trapped them in cages, forcing Astral to face Number 96 in a Duel, while constantly threatening Yuma's life. After Astral and Number 96 tied the Duel, Vector triggered an explosion within the ruins and fled with Number 96. Kite Tenjo saved Yuma and his friends from the collapsing ruins.

Number 54's Ruins (Colosseum)
The colosseum's ruins were located in Spartan City under a small lake, and its legend is well known to the Spartan City citizens. It is where the greatest gladiator to have existed battled using only his bare hands, and won every battle he fought. The gladiator was also the friend and rival of the prince of the land, whom he battled with many times. During their final fight, the gladiator was framed by the people close to the prince, who saw the gladiator's possible victory unacceptable. The gladiator was placed under false charges, and despite his pleas of his innocence and the prince defending him, the gladiator was executed.

According to Dextra, the residents believed the ruins were haunted by the gladiator's spirit because of his grudge against his unjust fate. Nistro believed the gladiator simply wished to fight more and regretted that he never finished his battle with his rival. The ruins was where "Number 54: Lion Heart" slept, protected by a large spirit in Spartan warrior armor.

In order to reach the ruins, Alit used traps to destroy the surroundings of the lake, draining it. When he tried to take the ruins' "Number", its guardian tried to repel Alit, however Alit was able to overcome the guardian's power and reach the "Number" card. Alit had his own nostalgia from these ruins when he explored them, and the guardian also seemed to recognize Alit.

After defeating Alit and a brainwashed Nistro with the help of Dextra, Yuma finds an Conqueror's Coin from his father in the ruins, and obtains its "Number".

Number 46's Ruins (Mountain Palace)
Unlike the other ruins, these ruins are very grand and lavish, with a traditional Chinese-style decor. The Number Guardian is Jinlong, who resides within the palace walls from atop a tall mountain.

Jinlong was originally Misael's pet dragon, who guarded the land alongside him. When disaster struck, a shaman, who was an agent of a neighboring nation, convinced the population that Jinlong was responsible for the disaster. Jinglong was tortured, but Misael continuously protected him to convince the others that he was not responsible. Unfortunately, the opposing forces attacked, killing both Jinlong and Misael.