On their way back to the world of the living Ichigo, Rukia, Orahime, Renji, Chad, and Uryu from the soul society while using the dangai they are hit by the cleaner and sent to the world of Pokemon, now suck there with no way to get back they try to make the best of it

Ichigo attends dual academy (yugioh universe, has no soul reaper powers but can see and talk to spirits)

After getting his powers back ichigo discovers he's a demigod/god on his mothers side (descendent or Artemis herself) and goes to camp half blood to learn about his mothers gifts. Starts at lightning thief, cameo ages unless paired.

Princess serenity (Usagi) isn't the only child of the queen, she had an older brother, and that prince was reincarnated as a certain orange haired substitute soul reaper