This time I tried out a different pairing, Sun x Lillie. Though, it's strictly platonic in this fic. But I do hope that you enjoy reading it!
Another challenger was defeated as their Gengar fainted due to Incineroar's Malicious Moonsault attack. Thus, the first Alola Champion, Sun, defended his title yet again. It has been like that since the Kanto-born Trainer took the helm as Alola's Pokémon League Champion by triumphing over Professor Kukui, the founder of the Alola League. Every once in a while, prospective Trainers would come up to Mount Lanakila in order to battle Sun in the hopes of capturing his title, though none have accomplished such a feat.
After both Trainers returned their Pokémon back into their Poké Balls, Sun congratulated the Trainer for making it this far, and wished for them try again next time. The trainer thanked the boy as they left the Champion's room.
Tired, Sun retreated to his throne that was provided by the Pokémon League, though he wouldn't mind it being a bit more comfortable. With a sigh, he looked back to events that led up to this point. From moving to the Alola region with his mother, becoming friends with people such as Hau and Lillie, completing the Island Challenge and becoming the Champion, to Lillie's farewell. The Alola Champion rummaged through his backpack, and soon grabbed out a Poké Doll that Lillie has bestowed to him.
He gazed at the object that belonged to one of his best friends. Before Lillie had left to the Kanto region in order to cure her mother Lusamine of the neurotoxins that was caused by the Ultra Beast Nihelego by seeking out a certain someone, the once apprehensive girl gave Sun a Poké Doll so that he could remember her at any given moment. As painful as her departure was, Sun knew that it was inevitable. He accepted that Lillie had fully grown to become an independent person, especially when she changed into her "Z-Form" and during the time when she flat out called her mother out in the Ultra Space by pointing out her flaws all in the name of being a "good mother" to the former and her brother Gladion.
Nebby, now Solgaleo, sorrowed over Lillie being gone, but the fact that she entrusted Sun to be its Trainer nulled the Legendary Pokémon from grieving its owner for too long. Sometimes, Sun would let Nebby play with the Poké Doll, despite its size. It wouldn't let go of the prized possession for quite some time.
Sun imagined himself venturing off to the Kanto region, visiting places such as Cerulean City, Red's hometown of Pallet Town, the Viridian Forest, or better yet, reuniting with Lillie and talking about how things have been in Alola. However, he shook those thoughts away because it sounded selfish to him. This was something that Lillie had to face head on without any of her friends' help, and he wondered if she encountered any new friends in Kanto.
Despite at the start that Lillie didn't want to become a Pokémon Trainer because she couldn't stand to see Pokémon getting hurt, she had second thoughts because of how Sun handled it. The blonde was intrigued by his battle style and the way that he took care of his Pokémon, showing love and care to them. Sun began to think if she was taking on the Gyms in Kanto because even though she wanted to make her mother healthy and well again, she wouldn't want to miss out on encountering strong opponents in order to better herself and her Pokémon. The Kanto native mused of Lillie one day challenging him for the position as the Alola Pokémon League Champion, and happily telling him that his mother was completely cured. That would be a sight to see in his eyes; just knowing how strong Lillie would have grown over the course of her time away. In Sun's honest opinion, the best feature about Lillie were her bright smiles. He hoped to see it again one day.
No matter how far they were away, they had something to remember each other by. Whether it was a typical item or one's actions, it would always be considered a memento. They would always be the best of friends. It brought a soft smile to Sun, directing the expression onto the item in his possession.
Suddenly, footsteps were heard in the chambers. Alerted, Sun placed the memento back in his bag as he stood up from the throne.
His next challenger appeared, and it happened to be the brother of the person who invaded his thoughts.
"What does a Pokémon Trainer really need to be successful?" Gladion questioned, his eyes locked onto Sun's.
Not expecting an answer, Gladion spoke out again. "I guess everyone might have their own answer. But for me…" He then proceeded to pull out a Poké Ball from his pouch.
"I want the strongest rival for myself."
With a smirk, Sun reached for his own Poké Ball as well.
He had his own answer to Gladion's question, but it would have to be shown in battle.