Prologue

Is it possible to be friends with, or even have romantic interests, in someone if you're their imaginary friend?

There exists a society of imaginary people, known as imaginary friends. Assigned to children at young ages, they live for as long as they are remembered by the child, which usually lasts for six years. The exception to this rule is Killua, the imaginary friend to Gon. Having lived for years past the average, he has to face some things that other figments would never have to; be offered something that both he and Gon never thought would be possible.

(Based off of a prompt I saw about being reincarnated as child's imaginary friend and gave it my own spin)
(Short story, gonna be pretty damn fast paced)