This Piplup is a Water-type Pokémon. It was chosen by Dawn after they saved each other from the group of wild Ariados. Piplup doesn't really seem to like the idea of evolving, so it holds an Everstone. Though Piplup is a male, he wears cheerleading outfits while cheering for Dawn in contests.
Piplup when it was introduced from the beginning as being serious and arrogant but is also a little bratty. His arrogance causes him to become defenseless or being fainted in battle. Piplup's best friend is Ash's Pikachu upon meeting with both Ash and Brock to Dawn and mostly being his companion in their journey. Like Bulbasaur, Squirtle, Pikachu and Snivy, Piplup does not want to evolve and wants to be stronger. Piplup also became friends with Dawn's Buneary and Pachirisu as well as Ash's Turtwig before its evolutionary stage.
In Memories Made Of A Bliss! which is the finale of Diamond and Pearl series, Piplup was deeply emotional and does not want to be parted ways with its best friend Pikachu which it angrily runs away and cries not to come back but Pikachu reassures they will be back soon making the two emotionally cry together. Piplup gains his confidence back after teaming up with Pikachu to stop Team Rocket in their final battle.
When Dawn reunites with Ash with his new friends, Iris and Cilan in the Unova region, Piplup has a strong rivalry with Ash's Oshawott due to both are Water-type Starter Pokémon are competing and fighting each other because both had a huge crush on the Mythical Pokémon, Meloetta upon her introduction.
Piplup was the first Pokémon Dawn ever had. They met in the first Diamond and Pearl episode, Following a Maiden's Voyage!, when the starter Pokémon from Professor Rowan's lab ran off. Dawn decided to try and find them, and Piplup was the first one she found. By the time the rest of the Pokémon were recovered, Dawn had grown attached to Piplup, and decided that it would be her Starter Pokémon.
Dawn's Piplup can be stubborn at times and it's also very proud like Piplup are. Overall, though, it is loyal to Dawn, and has helped her and her friends many times both in and out of battle (but always got lost when leading). Piplup has been shown that he deeply cares about Dawn, such as in the episode Stopped in the Name of Love! where Piplup's time for evolution has finally come. Piplup however refused to evolve out of fear that it would start disobeying Dawn just like her Mamoswine after evolving from Piloswine however the main reason he chose not to evolve is because the day he and Dawn meet was the day they chose each other to be their partners and wanted to stay her Piplup forever. In order to stop his evolution, Piplup transferred the energy of evolution powering up his attack Bide. Dawn respected Piplup's choice as she got an Everstone from Nurse Joy and decided to keep it by her side. Piplup has also been shown to have developed some kind of rivalry with baby Cyndaquil regarding Dawn's attention.
In the episode Where No Togepi Has Gone Before!, Piplup is confirmed to be male along with Pikachu, Croagunk and Meowth due the effect of Attract used by female Togepi. Even though it is seen holding poms poms during Ash's battle with Roark.
Piplup has recently become a target of Gible's Draco Meteor attacks as every Gible's Draco Meteor manages to hit Piplup no matter where he is. In the episode "Piplup Gets Separated", Piplup is once again hit by the move but is even more saddened when he notices that Ash and Dawn are paying more attention to Gible than to him. Jealous, Piplup runs away only to bump into disguised Team Rocket who pretend to be the aids of Professor Rowan. Suddenly, a wild Rhyperior starts rampaging splitting everyone up. In the same episode in order to save Dawn, Piplup learns a powerful move, Hydro Pump and so manages to attack Rhyperior.
In Piplup, Pansage and a Meeting of the Times!, he returns along with Dawn in East Unova, and is identified by Ash's Pokédex to show Iris. Later in the episode, he falls in love with Meloetta and fights with Ash's Oshawott. He later battles Cilan's Pansage and wins, despite the type disadvantage and is revealed to have learned Ice Beam (likely to counteract the weakness to Grass-type moves and Grass-types in general, who are weak to Ice moves).
|Bubble Beam +||Following A Maiden's Voyage!|
|Peck||Following A Maiden's Voyage!|
|Bide||Following A Maiden's Voyage!|
|Whirlpool||Getting The Pre-Contest Titters!|
|Hydro Pump +||Piplup, Up and Away!|
|Drill Peck +||Piplup, Pansage and a Meeting of the Times!|
|Ice Beam +||Piplup, Pansage and a Meeting of the Times!|
|Headbutt +||Expedition to Onix Island!|
|+ indicates this Pokémon used this move recently.*|
- indicates this Pokémon normally can't use this move.
- Counter Shield
- Sweet Kiss Bubble Beam
- Discharged Whirlpool
- Water and Fire Whirlwind
- Dawn Plan A
- Aura Sphere Bubble Beam
- Aura Whirlpool
- Sky Attack Peck
- Hydro Volt Tackle
- Flaming Whirlpool
- Big Bubble
- Piplup is the only Sinnoh starter Pokémon to be owned by a main character other than Ash, as well as the only one to never evolve.
- Piplup almost did, but kept fighting it off until receiving the Everstone.
- A running gag during Sinnoh after Ash caught Gible was that it would be on the business end of Gible's repeatedly misfiring Draco Meteor attacks.
- One only hit it because Barry's Empoleon, the intended target, deflected it away on Barry's command to "hit it back".