The adoption thing was technically Green's idea. But Diantha was the one who actually did something about it.

He had first planted the seed in her mind when they were escorting the Vaniville kids to Pokémon Village. Diantha was talking about how adorable they were, and also how much she admired their courage and their determination to save the Kalos region, and really the whole world. Green had glanced at her and said, "If you love them so much, why don't you just adopt them?"

Diantha stopped walking, prompting Green to stop as well. She met his eyes and gave him a cool smile. "That's not a bad idea, Green. Perhaps we should adopt those kids."

He raised an eyebrow at her, then sighed and continued walking again. "I wonder what their parents would think about that."

Diantha narrowed her eyes at him. "Well, you won't have to keep wondering for long," she finally said, though he didn't really hear her. She fell into step beside X on Y's Rhyhorn, and attempted to make conversation with him. Green gave her a quizzical glance over his shoulder, but she took no notice of it and he turned his attention back to the path before them.

Those were the last words they exchanged before the showdown with Team Flare. He assumed she had forgotten about the whole thing after that, but he could not have been more wrong.

Three months later, Green received a Holo Caster message from Diantha. In it, she informed him that she had kept in touch with all five of the Vaniville children after they defeated Team Flare, and she even helped Shauna and Trevor find jobs in Lumiose City. Y was living on relatively good terms with her mother again despite continuing her training as a Sky Trainer, but X was still essentially living on his own; he had only just moved back into his house, which was totally empty except for himself. Apparently, his parents were working in Kanto to establish Contest halls in the region, and had no plans of returning to the Kalos region anytime soon.

"You should talk to them," the message concluded. "They're right there in Kanto. It's much more convenient than me trying to contact them from Kalos. Just ask them for permission to apply for legal guardianship of X."

He was a little surprised at first, and he wasn't really sure what to think of her proposal. But eventually, he came up with a response. "I have my responsibilities as the Viridian Gym Leader to think about," was Green's reply. "I can't be taking care of a kid hundreds of miles away."

"I've never known you to make excuses, Green."

That was the only line of Diantha's second message. He knew that she was right; he had been doing a rather poor job as Gym Leader because he was more interested in traveling to other regions. Plus, he wouldn't mind returning to Kalos to see those kids and Diantha again. He would never admit it, but he had been a bit more eager than he usually was to open those messages from her. Perhaps now was the time to give the title of Gym Leader to someone else who was more interested in the job than he was.

The rest of the process went much smoother than he'd expected. X's parents had heard of both Green and Diantha and were quite contented with leaving their son in their care. Diantha took care of the legal proceedings back in Kalos, while Green worked with the Pokémon Association to select his successor as Gym Leader.

Finally, over a year after he left Kalos, Green was ready to return. "I'm proud of you," his grandfather told him. "It's no easy task to have a family, but I've always believed you could handle it someday."

"Thank you, Grandpa," Green said, climbing on Charizard's back. Daisy wasn't sure that Charizard could manage the flight all the way from Kanto to Kalos, but Green trusted his partner. Charizard stretched its wings and took off. Green took a deep breath. He was on his way to see his new family.

A/N: If you're interested in what happens next, check out my story "Gratitude".