Lights of Another Dimension

Thirteen-year-old Dominic, bullied since he was nine, can turn into all species of Pokémon. After an attempt to kill him and his sister, Karen, the two end up in a distant dimension, one where Pokémon live everywhere, and Pokémon trainers catch and battle them. Dominic soon finds out that he was chosen to have this gift, and needs to use it to bring Pokémon back into his world.