Mitsumi
Mitsumi is Hareta's traveling companion who is known for being quite good at Pokémon Contests. She was the strongest member of Team Galactic until she defected. She gave the National Pokédex to Hareta in the bonus scene at the end of the Diamond and Pearl Adventure! book.
Pokémon
Infernape
Infernape is the strongest Pokémon Mitsumi has. Its first appearance was during the Hearthome City Contest. Its only shown moves are Mach Punch and Fire Spin.
Leafeon
Leafeon is a Pokémon that works well with Infernape in battles as well as contests.
Glaceon
Glaceon was briefly shown in the last book of Pokémon Diamond and pearl.
Its only shown move is Ice Beam.