When Dedenne first appeared, he dropped a berry, falling in Bonnie's hands. Later, Dedenne attacks Bonnie and Pikachu because of the berry. When Bonnie gives the berry back to Dedenne, the Fletchling that Ash Ketchum captures later on steals the berry and swallows it, upsetting Dedenne and making him ran away with tears, which tipped off Bonnie.
Dedenne came while Bonnie is petting Fletchling and steals the food. They chase him for a while. Later, Pikachu and Dedenne are being chased and harassed by Team Rocket and James' new Inkay. Later, they become friends and look for Ash, Clemont, and Bonnie. When Team Rocket came back, Dedenne and Clemont battled against Inkay and defeated it with Nuzzle and later teams up with Pikachu to deal the final blow using Thunder Shock and Thunderbolt combination to make Inkay slash the balloon in explosion to blasts Team Rocket off, giving pleasure to Bonnie. Later, Bonnie and Clemont catch it, but Bonnie starts to carry Dedenne in her little purse after it fell asleep. Before it fell asleep and being kept in Bonnie's little purse, Bonnie remarks him and Pikachu are little twins.
When Dedenne first met Ash's Goomy, Goomy showed intense fear of him because Dedenne is a Fairy-type Pokémon. However after Dedenne protected it from Team Rocket, Goomy opened up to Dedenne and became a very good friend.
Towards the end of the series, Dedenne felt incredibly upset that everyone is about to leave on their respective journeys and ran away. When everyone found Dedenne, Bonnie comforted him and told him that she wants Dedenne to be her partner when she becomes a trainer. Afterwards, Clemont, Bonnie, and Dedenne bid their farewells to Ash and Serena.
Dedenne is similar in personality to Snorlax. He can be very gluttonous, and after his meal, or if he uses a lot of electricity, Dedenne goes to sleep in Bonnie's purse.
He later became friends with Ash's Pikachu after they are separated from Ash and the group as both are seen conversing with their electric attacks from their cheeks and always being protected by it when they are after by Team Rocket as well as teaming up to defeat James' Inkay with both of their Thunder Shock and Thunderbolt combination.
Like Brock's Bonsly, he can be seen as cheerful, friendly, energetic and childish. He is also very fond of Bonnie after being captured by her brother, Clemont and his actions are also similar to Cilan's Dwebble who is also fond to Cilan. Also, Dedenne is a very loyal friend and would go out of his way for them no matter what. Dedenne is best friends with Ash's Goodra and a good friend of Squishy during their time in Bonnie's Bag.
When Ash and Serena are about to depart by plane in the finale episode of the XY series, Dedenne, like Dawn's Piplup, becames deeply emotional and upset whenever he sees his friend Pikachu go and runs away much like Piplup previously did to him when Ash and Brock are about to depart by ship to Kanto.
- Megumi Sato (Japanese and English)
- Dedenne is the first recurring wild Pokémon to be caught by another character besides Ash.
- Dedenne is the second Electric-type Pokémon to shock Bonnie. The first was Ash's Pikachu.