Kenny is the Pokémon Co-ordinator from Sinnoh and Rival of Dawn.
He lives in Twinleaf Town, the same town as where Dawn lives. Kenny always calls Dawn "Dee Dee" because of Dawn's past. Kenny also wants to be a top coordinator. Kenny's Starter Pokémon was a Piplup, now an Empoleon. He also had Ash's Turtwig train a bit about the Energy Ball, which Ash managed to teach Turtwig in full.
During the Sinnoh Grand Festival, he attempted to make a grand combo using Floatzel's Whirlpool against Empoleon's Flash Cannon, but failed and did not go to the next round. After the Grand Festival, he met up with Dawn and offered to go on the journey together. While Dawn had to go with Ash to support him in the League, she yelled to Kenny she will be there for him.
Having evolved from his Prinplup in the run up to the Grand Festival, Empoleon was used during the appeal round. Like before, it is Kenny's powerhouse and has many powerful attacks including Metal Claw, Bubble Beam, Mist and Flash Cannon allowing it to be an incredibly strong Pokémon within Kenny's team.
Kenny's Alakazam has only been seen once, during his Contest Campaign in Floaroma Town. It has a variety of attacks at its disposal like Shadow Ball and Hidden Power so it can hold its own in battle easily.
Kenny's Breloom has only been seen once, during the Solaceon Contest, as well as during a training battle against Ash's Turtwig. It has many powerful attacks including Mach Punch, Stun Spore and Energy Ball at its disposal.
Machoke is another one of Kenny's Pokémon that Kenny utilized during the appeals process. As it was used in the appeals as opposed to battle, very little of it's battle skills are known as it just showed off it's physical strength.
Kenny obtained a Floatzel prior to the Grand Festival in Sinnoh. Floatzel has some powerful attacks such as Whirlpool at its disposal which it used in conjunction with Empoleon to create a dazzling appeal, however it slipped up during the appeal which caused Kenny to fail the appeal round.