Fantina was born in France, but later came to Sinnoh and learnt English. She speaks a mix of French and broken English. Upon arriving in Sinnoh, she decided to become a Contest performer, so she dresses up in fancy outfits for Pokémon Contests. People recognized her being very powerful, so she was offered by the Hearthome City mayor to become a Gym Leader. She accepted it, becoming the fifth Gym Leader in the Sinnoh region, specializing in Ghost-types!
Fantina was given a Pokémon Egg by her father upon arriving at Sinnoh. It hatched into a Drifloon, becoming her life long best friend. She trained from day to day in Pokémon Contests, and later, it finally evolved into a Drifblim!
Egg → Drifloon → Drifblim♀
Whilst in Sinnoh, Fantina traded her Tangrowth away in exchange for a Misdreavus. Afterwards, she trained it from day to day in order to become powerful. It evolved into Mismagius, and like she wished, it became extremely powerful!
Misdreavus → Mismagius♀
Fantina met Gastly whilst training with her Mismagius outside Hearthrome Gym. They befriended each other, becoming friends. She later captured it. Later, it evolved into a Haunter whilst having a Gym Battle, then later into a Gengar!
Gastly → Haunter → Gengar♂
Fantina took a trip to the Kalos region to participate at the Pokémon Contests there. She befriended a Honedge, becoming good friends. She later had to leave Kalos and go back to Sinnoh, so she captured Honedge and went back to Sinnoh with it. Afterwards, she trained it extra hard to become an even stronger Doublade!
As Fantina was traveling in Kanto, she met a shy Tangela whom she became friends with. Afterwards, she captured it and came back to Sinnoh with it, thus evolving into Tangrowth. She realized it had more interest in battling than participating in festivals, so Fantina traded Tangrowth away to a Trainer in order for a Misdreavus.