Piplup serves as Dawn's Water-type First Partner Pokémon, originally received from Professor Rowan in Sinnoh. Their partnership ignited when Dawn rescued Piplup from wild Ariados; initially indifferent, Piplup witnessed Dawn's attempt to shield him and chose to defend her instead of fleeing. This act of mutual protection forged their bond, leading Dawn to select Piplup as her primary partner. He carries himself with proud seriousness and occasional brattiness. His strong self-esteem makes accepting food or care from humans distasteful, and pride often hinders his obedience. Yet deep loyalty defines him, especially toward Dawn, frequently seen held in her arms or perched on her shoulder or head. Ash's Pikachu became his closest Pokémon companion, their bond strong enough for emotional farewells. He also formed friendships with Ash's Infernape and Torterra. Piplup steadfastly refuses to evolve, aspiring to prove his strength without changing form. This resolve stems from three core reasons: fear of disobeying Dawn after witnessing Swinub's disobedience post-evolution into Mamoswine; inspiration from Pikachu's similar determination; and a desire to remain the specific Piplup Dawn first chose. He actively countered evolution energy using Bide and later wore an Everstone provided by Nurse Joy. Significant development occurred through conflicts. A running gag involves him repeatedly struck by Ash's Gible's misfired Draco Meteor. Feeling neglected during Gible's training once, Piplup ran away. He encountered Team Rocket disguised as "Pokémon Rescue Corps," who manipulated him into luring Pikachu into a trap. Confronting a rampaging Rhyperior during the ensuing fight, Piplup learned Hydro Pump to protect Dawn, showcasing heightened loyalty and combat growth. His competitive nature flares around other Water-types. In Unova, he developed a fierce rivalry with Ash's Oshawott over mutual affection for Meloetta, involving physical clashes and contest battles before becoming friends. Piplup also admires Goh's Inteleon for its cool demeanor. He actively participates in Dawn's contest performances, sometimes wearing cheerleading outfits despite being male. He collaborates effectively with her other Pokémon in double performances, though occasional friction arises with teammates like a baby Cyndaquil vying for Dawn's attention. During the "Arceus Chronicles" special, temporal distortions caused by Dialga and Palkia temporarily devolved Piplup into an egg. Following Alternate World Team Rocket's defeat, Arceus restored all affected Pokémon, including Piplup. His known moves include Bubble Beam, Whirlpool, Peck, and Hydro Pump. Piplup's battle style blends strategic contest techniques with raw determination, often overcoming challenges through critical moment breakthroughs like Hydro Pump.