Prologue - A Long Time Ago...

When Lusamine was little, she had dreamed of meeting a super rare Pokémon. When she grew up, she used a machine to harness to power of an Ultra Wormhole and forced Ultra Beasts to come out. She endangered Alola...
...and that is why she got banished... by the new champions of Alola, Eliole and Cerene.
They ended up marrying and having kids, which they named Sun, Ash, and Moon.
Strangely, Lusamine married a man named Mohn and also had three kids. They're names were Gladion, Lillie... and then there was Violet.