Besides Earth Land, where the story primarily took place, there was another parallel world in the world of Fairy Tail, one that stood opposite to Earth Land: Edolas.
In many ways, it was similar to and the reverse of Earth Land. The people had the same names and appearances, but different personalities, identities, and so on.
Moreover, the people there possessed no magic power themselves and could not use magic. They had to rely on tools containing magic power in order to cast spells.
For example, Mystogan of the Fairy Tail Guild used an alias. His true identity was Jellal of Edolas, and after coming to Earth Land, he used various staffs embedded with Magic Crystals to perform magic.
Adam's current inspiration for casting spells through a full set of equipment came from Mystogan—or rather, from the way Edolasians cast magic.
Furthermore, the dragons of Edolas were humanoid. The Fairy Tail Guild's advisor, Porlyusica, was actually Celestial Dragon Grandeeney of Edolas.
Edolas also had a race called the Exceeds, winged cats—the race Happy, who accompanied the protagonist Natsu, belonged to.
Example after example showed that people from Edolas coming to Earth Land was no isolated case.
Similar events must have occurred in the past. Therefore, in Earth Land, those forces with genuine foundations and inheritances ought to have records concerning Edolas.
With this avatar's abilities, it would truly be difficult to create the ruins in the gap between Edolas and Earth Land. It would take a great deal of effort.
But if the ruins were disguised as having originally existed in the gap between Edolas and Earth Land, only to suddenly appear in Earth Land now...
That was actually a pretty good choice!
Although creating that disguise would not exactly be easy either, the cost-effectiveness was much higher by comparison.