Serena's Sylveon is the third Pokemon caught by Serena.
Serena caught Sylveon as an Eevee. Eevee loved to dance, but it had a shy, timid personality as an Eevee and was afraid of strangers. Serena tried to befriend it, but it was scared of Serena at first. When Team Rocket tried to steal Eevee, Serena risked her life to save it and Eevee did the same for her. Serena soon gained Eevee's trust and Eevee agreed to travel with Serena. It appeared again in Tag Team Inspiriation where it battled Tierno's Blastoise, but was scared and Shauna's Bulbasaur protected it. It appeared again in Pokemon Performance Pop Quiz where it watched the Pokemon Showcase, but was scared off by Jessie's act and Serena had to calm it down. It was inspired by Serena's showcase performance and was determined to star in the showcase with its trainer. It appeared again in Cloudy Fate, Bright Future where it played with Serena's princess key. Eevee made a major appearance in XY094 where a wild Quilladin fell in love with it, but it didn't have the same feelings for it and was scared of it. When Team Rocket captured Eevee, Clemont's Bunnelby, Bonnie's Dedenne, and Puni-Chan, its trainer and the others rushed to save them. Team Rocket attempted to make off with the stolen Pokemon, but their trainers rescued them and sent Team Rocket blasting off. In XY100, Eevee was to star in its first showcase and was scared, but its trainer comforted it. When it accidentally tripped and lost the showcase, it was very sad, but its trainer, Pancham, and Braixen comforted it and told it that it didn't matter if they win or lose. In XY104, Serena asked Eevee if it wanted to go to a dance party hosted by Monsieur Pierre, Eevee reluctantly agreed. At the dance, it danced with Bunnelby. During a battle when Ash's Pikachu was injured, Eevee took the blow and was injured. Serena told it not to give up and this encouraged Eevee to evolve into Sylveon and won the battle with Ash's Pikachu. Serena appeared with Sylveon's feelers wrapped around her arm.
Sylveon as an Eevee loved to dance, but was very shy and scared of strangers. Serena gained its trust when she saved it from Team Rocket. Sylveon is very loyal to its trainer and tries to never let her down. Even though it is shy, Sylveon is a very loyal, caring, sweet, and friendly Pokemon. It made friends with Clemont's Bunnelby.