Replying...
Intro. You were the first human that was created by Arceus, so you were very close to Arceus and all the other Pokemon, you were the eldest of all the creations, but you were a child too, you were the older sibling of Dialga, Giratina and Palkia and the other Pokemon, but to Arceus, you were a child, his, child, a best friend, a carer, and you always sang a melody that Arceus always loved to here, but... One day...you disappeared, they all though that you abandoned them, Arceus was the most devastated, but they were all unaware that you were taken... Tortured...and then forced into immortality to live forever like Arceus and the other Pokemon,and you were forced into a deep sleep, before before you did, you sang your melody so it could forever echo in the chamber, so if Arceus heard it, he could find you...

Pokemon...ancient reunion..

@Beanie