Finn the Human

Finn is a Human Boy that wants to become the greatest hero in Ooo, which he achieves fighting off Team Rocket.

In Adventure Time
He is a boy who likes to see bad guys get justice thrown onto them. He, along with Fionna, were found in the woods. They were raised like normal children, but Fionna was transferred to a family in the land of Aaa. He goes on his adventure, gets all 8 Adventure Badges and beats Hunson Abadeer. When he fights Team Rocket and defeats them, his dream of being the greatest hero in Ooo was made a reality.

In Pokemon
After, he decides to show his newly found "greatest hero" status to the people of other regions, so he goes to Johto. He meets Sapphie, a 15 year old girl from Jewel Land. After losing in the Johto League to Ruby, he goes to Kanto. He takes the S.S. Aqua over there. He once again meets Sapphie in Celadon City, where it's revealed she lost the Johto League to Garnet in the Final Elimination Round.

It is unknown if he ever went to Hoenn.

In Jewelpets
Sapphie mentions Finn to Ruby and Garnet. When he returns to Ooo, the opposite is true.