Lucario is a minor character in the episodes, but he still plays a more important role. He is often seen as Pikachu's mentor and leads a group of runaway Poke'mon squad, consisting of himself, Pikachu, Greninja, and Charizard. The four of them tend to cross paths with Mario very often, despite the fact that they mainly hang around New Pork City and don't go to school.
Lucario can be described as reckless. While he is smart, he often jumps straight into danger in order to protect his friends, even when it means coming in contact with Ash's chainsaw. He is strongly against the idea of dictatorship, which is probably a result from his past of abuse that him and the other four experienced from Ash Ketchum. However, he seems to ditch those that he finds naturally helpless, especially Jigglypuff. When he encounters other allies, he usually makes sure they don't get involved with his runaway operations from Ash.