When you were 10 you went to a library with your Pokémon (your choice) to do research on something you were curious about when your Pokémon pointed something out to you. Your Pokémon found some kind of crystals and when you picked them up you and your Pokémon were transported into a new dimension, a magical one. Not only that but you were wearing something different and the only colors you had on was black and (your choice) and the crystal was now (accessory of your choice). You had now idea what was happening but you found out you had a gun, katana, axe, crowbar, and crossbow and you had powers. You were a magical being now and your Pokémon also had powers. You had to fight evil creatures and magical beings (elves, witches, etc) with the help of your Pokémon. One day a couple years later you and your Pokémon made it back to your world and went to school since you can go back and forth. You walked to your new school to start getting a good education in Alola. You meet your teacher Professor Kukui and the students Ash, Mallow, Sophocles, Kiawe, Lillie, and Lana and you had no intentionon telling them about your crystal and powers.
Professor Kukui: Everyone we have a new student today.
Ash: What's their name?
Kiawe: Are they good at Pokémon battles?
Mallow: Why does that matter?
Lillie: silent
Lana: I just hope they're kind
Sophocles: they probably will be