Updated: 1/28/19 This is the intro to the reworked story. Hope you enjoy.
There was once a fairy tale told to the children of Sinnoh long, long ago. The fairy tale was from a time when people lived in castles and humanity was still pretty young, as it involves the prince of the royal family and his loyal Pokémon.
It's said that a young prince was to marry the princess of a neighboring kingdom, as royalty could only marry other royalty. This arranged marriage was set to happen when both the royal children turned fifteen, which would solidify relations between the two kingdoms and give the Kingdom of Sinnoh a future queen to bear a heir to the throne.
The young prince was very displeased about this, as was the princess. So the night before the princess turned fifteen, she ran away and left the country to live a life of her own choosing. Now the wedding was cancelled, and no other neighboring kingdom had a unmarried princess. Sinnoh was without a potential queen, and the royalty began to panic.
Now that his life was his own again, the prince could now do as he pleased. For the next few years the prince traveled his kingdom with his loyal Gardevoir, and met many of his subjects and had many great adventures. All was well during this time, however that came to an end when the king became sick and passed away very quickly. The young prince would now be king, but another of the royal family had his eye on the throne.
Since the young prince was unmarried, his uncle could claim the throne as he was married with a heir already. The prince was given a choice. Get married, or lose his claim to the throne.
Once again the prince felt pressure to marry, but not a single princess would be able to accept his hand. Since he would have to vacate the throne, the prince became very depressed as his last day on the throne approached. The night before his last day, the prince spent his time with his Gardevoir in his study. He spent nearly the entire night just talking to his companion. That's when the answer became clear.
The prince looked at his beloved companion and realized who his heart had belonged to. The beautiful young woman in front of him, his beloved Garedevoir.
The prince would take his Pokémon's hand in marriage. She was intelligent enough to do anything a human could do, and since she was born and raised in the royal family she was technically of royalty. So the prince would marry his beloved partner who was more than overjoyed to do so, as there was no bond deeper than what these two lovers shared. The nobility was very skeptical at first but the prince promised an heir even with another woman if he had to. With hesitation they accepted, and the King would have his Queen.
The beautiful Gardevoir ruled as Queen to the King and this would lead to a golden era for the Kingdom Of Sinnoh. So much so, that marriage between human and Pokémon would be considered ideal for many kingdoms and the relationship between human and Pokémon grew even closer.
The young prince and his beloved Gardevoir brought a new understanding of love to the world, one that would fade eventually but return just as strongly many years later. This is the tale of how that love returned to the world. This is the tale of Athena.