"Strength isn't quantifiable by Power, but in the ability to make tough choices"
飛龍, "Hiryū" literally translates to "flying dragon". It's name is that or Dragonfly because it's a Dragon Type that can fly.
As a Dratini, it was raised by its family. Its father the Dragonair, and a sibling Dratini. They lived relatively comfortably isolated from humanity for thirteen years, which is still a child age for this species as they are long lived.
As a Dratini, she was lived with her Father Dagonair and sibling Dratini. They lived in a large pond in a meadow with other wild Pokemon. The rare human that knew of this place kept it a secret, so the Dratini was able to live the first 13 years of her life comfortably.
However, one day everything changed. Team Rocket discovered the meadow and started capturing the rare pokemon that lived there, including Dratini's father the Dragonair.
With the help of trainers that wanted to save the pokemon from being kidnapped, she was able to fight back against the criminals and free her dad. However, even though team rocket had been defeated, the family could no longer live here. This place was known to humanity now, and was no longer a safe place. Her father encouraged her to follow the kind trainer which had helped her free him, which happened to be Red.
Though saddened that she had to leave her family and home, Dratini (now Dragonfly) took Red (then Dawn)'s offer to follow him as part of his team. Though she had problems with her new setting, she was quickly able to get along with Red and the rest of his team. The other Pokemon were friendly and inviting, and always willing to explain something if she didn't understand.
A part of her always ache to return home. Her quiet little Meadow, her childhood home, was no longer somewhere she could ever return to. Though she might like her life now, she feared it happening again. She never wanted any of her new friends to have to go through what she did.
Yet, she didn't know how she would prevent this. She wasn't able to stop Team Rocket from ruining her home, what if it happened again and she was still unable to defend what she loved?
Filled with the desire to defend its new family, Dragonfly evolves into Dragonair. She now had the power that her parent did, and felt more confident and sure of her ability to defend whoever she needed to. She tirely trained to strengthen her dragon power, and helped win Red many badges.
As a dragon type, which are weak to ice, it had to learn how to adjust to the new climate that it would be living in. It would often huddle up into a coil and stay around the other Pokemon, especially Sunny the Arcanine, for warmth.
Despite the disadvantage, anytime it saw any of its teammates in trouble she would jump into help. Whenever wild Pokemon attacked, she was the first to fight for them. she would even take hits for them if necessary.
Slowly, her discomfort with the cold began to diminish. The dragon fire Within its heart grew stronger, eventually leaving her unaffected by the climate. She always stuck closest to her trainers side.
She was fiercely defensive of red. He had taken care of her and gave her a new home and family when she could no longer be with her own. Now red was in a situation where he was scared, just like her. He felt too seen. Everyone had their eyes on him when he just wanted to live a private life, which is exactly how dragonfly had felt.
Red had made a home of the mountain. He had a place to sleep in, he had Pokemon to cuddle for warmth, he had food, he had developed a routine and was familiar with the wildlife there, the pokemon and the pathways, and he had the Pokemon that would always be there for him.
So when Blue had climbed up the mountain to tell him to go back to humanity, and Red didn't want to, Dragonair would fight this battle fiercely.
SO. POKEMON BATTLE. 6v6. Pidgeot vs Pidgeot, Arcanine vs Arcanine, Big Fish vs Little Fish, Eevee vs Jolteon, Blue vs Red...
Blue has 3 Pokemon left, the one battling and 2 left, and Red only has 1 now, the other five fainted from battle. He's tense, scared, because losing means having to leave the place he's found a home for himself in. Found safety in, a place where him and his Pokemon have grown so attached to.
He calls forth the Dragonair, who struggles with the battle at first. Gyarados knew dragon attacks of its own yet was not damaged to the same way when Dragonair spat at it. Just as Gyados was charging an attack that would surely knock out Dragonfly, winning Blue the battle...
With the new power it defeats Blue's Gyrados, and the one after that. Now Red and Blue both only have one left, Red's Dragonite, and Blue's last Pokemon.... Charizard.
Dragonite attacks with its full dragon power, but Charizard dodges. He doesn't make any attacks of his own, instead focused on not getting hit. His trainer calls for an attack, but instead Charizard roars and flies upwards into the sky where it is followed by Dragonite.
Neither trainer can command their Pokemon from up there.
They roar at each other, Dragonite is angry and does not want to lose for the sake of her trainer. She knows his feelings and is intensely protective, but Charizard roars back. He similarly empathizes with his trainer, especially as he is Blue's starter Pokemon. It explains that Blue feels a similar fear to Red.
Charizard knows Blue truly fears that he might not be able to get Red back- and Charizard honestly does not know if it can beat Dragonite in battle. He asks Dragonfly if Red is really happy up here, if winning this battle is really best for its trainer or not. Red may be scared of going home, but it isn't true that he would be friendless with humanity. Charizard knows his very own trainer would do anything to get Red back, even climb up a cold dangerous mountain and battle him with every ounce of stregth he has.
Slowly the two flying Pokemon land back on the snow battlefield. Red commands Dragonfly to attack, but the Dragonite doesn't do anything and neither does Charizard. Red is confused, distressed, because he has to win this! But instead the Dragonfly approaches him and shakes his head. It forfeits.
All of Red's Pokemon surround him and give him a hug, understanding that Dragonfly's choice was the right one. They comfort him, and tell him that it will be okay. Red is disbelieving at first, but with the support of his Pokemon he's able to accept this as well.
Dragonfly along with the rest of red and blues Pokemon live in the gym that they co-own together.
Red's dragon Pokemon are famous for their immunity to ice. With no native fairy types in Kanto, and nary a dragon stronger than his, Red's Pokemon are often seen as without weakness.
Dragonfly is still very attached to her trainer as well as the rest of Red's Pokemon, but will often socialize with Blues Charizard and maybe getting protective of his Pokemon as well.