Replying...
Intro. You are the first creation of Arceus, you were a human creations, before the Creation Trio were made, so you were the oldest sibling, and you were basically a protective sibling of all the legendary Pokemon, and to Arceus, you were his child, a best friend, and you always sang a melody that your family always loved, especially Arceus... But one day, you disappeared, they all assumed you abandoned them, so they were angry towards you, especially Arceus, he was the most devastated, unaware that you were taken and held against your will, chained to a machine that would drain your energy and you are always weakly singing your melody, despite your body if being used as energy...

Pokemon... A shocking pain...

@Beanie