In truth, people and Pokémon weren't so different. Growth could happen in an instant.
The moment Greninja left the Borderlands and returned to Xu Mu, he'd had to choose to grow, to face things he'd never faced before.
He had to leave his comfort zone and become Xu Mu's shield.
But he hadn't expected Xu Mu to have little need of his protection.
What's more, his Little Master kept springing all sorts of surprises on him. Those mysterious, unknown powers always made him much stronger.
In just one year, he had surpassed his father.
Greninja had never imagined that, not even in his dreams.
What?
Was he happy about it?
Did that even need asking? Of course he was!
Obviously!
But was he nervous? Absolutely.
How could he not be, wielding power he hadn't built from the ground up himself?
Still, stay nervous long enough and you got used to it, didn't you?
Dragonite and Charizard had accepted it without a qualm. Greninja couldn't be the one to fall short.
He couldn't panic!
More than that, he needed a good reason to accept it.
Jokes aside, Greninja looked at Xu Mu in earnest.
There was something unusual in his eyes.
Xu Mu felt the same way. Companionship wasn't guaranteed to last forever, but given the choice, who wouldn't want their best friend to stay by their side?
In the end, Nobita had lost Doraemon.
Taichi Yagami had lost Agumon.
And Naruto had lost Kurama.
Xu Mu didn't want to lose Greninja, his very first partner, someday too.
The system's power was unknown. Even now, Xu Mu had no idea what to make of that mysterious force that stood above everything else.
But he was going to give Greninja his share anyway!
For one simple reason: Greninja couldn't be left behind!