Lucario is used by notable trainers Maylene , the third Sinnoh Gym Leader ; a tag-team partner known as Riley ; Cynthia , Sinnoh 's Elite Four Champion ; and by Bruno , an Elite Four member of Johto .
Lucario is a Pokémon that appears in the Nintendo DS versions of Pokémon Diamond and Pearl ; Lucario is used by Maylene , the third Sinnoh Gym Leader , a tag-team partner known as Riley , and by Cynthia , Sinnoh 's Elite Four Champion .