Fina is first seen piloting a strange ship in order to escape her pursuers. Her pursuer happens to be the Valuan admiral, Alfonso, who shoots her ship down and knock her unconscious. Luckily for her, Alfonso's ship is targeted for raiding by some Air Pirates who help her escape as well as loot the ship. When she awakens, she meets Vyse and Aika, who wonder why she wears such strange clothing. She introduces herself before Vyse is called to steer the ship back home. When they reach Pirate Isle, Vyse and Aika's home, Fina is confronted by Vyse's father, Captain Dyne, who asks her if she will be a threat to his family, his crew, and the other inhabitants of Pirate Isle or not. Fina shakes her head and says that she could never bring harm to people who saved her life even if she cannot remember where she came from. Later that night, Fina is stargazing with Vyse and Aika at the Lookout point. They see a falling moonstone crash into Shrine Isle, so Vyse and Aika decide to go there and investigate tomorrow.
Fina stays at Pirate Isle while Vyse and Aika go on their adventure, and then she is kidnapped by the Valuan Armada when they attack Pirate Isle. She is seen talking with Empress Teodora of Valua, who demands that Fina help Valua find the Moon Crystals to awaken the Gigas and rule the world. Fina flat out refuses, and is then led out of the throne room. She is later seen boarding a rail car in Upper Valua. Vyse and Aika outrun Galcian and manage to rescue Fina. They escape Valua by the skin of their teeth aboard the Little Jack.
After they arrive at Pirate Isle, Fina explains her story to Vyse and Aika. She is a Silvite and was sent to this world on a mission to find the six Moon Crystals that would control the the Gigas and prevent them from bringing destruction and raining ruin like they had done so long ago. She pleads Vyse and Aika to aid her in this quest, and depending on the player's answer, Vyse will agree without question or hesitate. Either way, the will be a strange squeaking noise coming from Fina's sleeve. Then, a small, balloon-like creature will come out, and Fina will introduce him as her faithful pet, Cupil. After Vyse gets permission from his parents to leave the island, they depart for their odyssey.
Throughout their journey to find the Moon Crystals, Fina will explain many of the characteristics of the lands that live under the different moons. Like the continent of Ixa'Taka, for example, is a lush jungle because the Green Moon rises over it. Many people in Ixa'Taka actually mistake Fina for their god, Quetya, and Fina explains that after the Rains of Destruction fell, Grendel terrorized the land and slaughtered all but a few primitive, tribal people before the Silvites could contain him, so they thought the Silvites were gods. When they attempt to retrieve the Yellow Moon Crystal that is stuck in Valua, they are attacked by Ramirez's flagship. Aika and Fina are then separated from Vyse and Drachma.
When Fina wakes up, she is seen on Clara's ship with Aika. After hearing about their plight, Clara drops them off in Nasrad to help them find the person they're looking for. Fina and Aika find half of a map that leads them to Daccat's Isle. They land on one side of it and make their way through the dungeons in search of Daccat's legendary treasure. After making it through, they reunite with Vyse and a pirate named Gilder who had landed on the other side of Daccat's Isle. The party travels back to Nasrad, only to find that it has been burned down by Ramirez. Stepping out of the flames, the admiral orders them to hand over the Moon Crystals, and Fina pleads Vyse to do as he says because there is no way they can take him on at their level. Grudgingly, Vyse does as she requests. Fina is held somewhere separate from the others and asks Ramirez why he would side with Valua. He does not answer. The next time she turns around to see who enters the room she's in, it is Vyse and the others. Now reunited with them, they escape Valua with the help of Prince Enrique.
They travel to Crescent Isle, the place where Vyse was stranded before Gilder rescued him, and build a base there for the Delphinus and the new additions to Vyse's beginning crew. And it is there that Fina explains Ramirez's origin. He too, is a Silvite. Not only that, but he was their best warrior, and Fina's best friend. They grew up together, and Fina considered herself like a little sister to him since he was the only one besides Cupil who could play with her. They were the only two close enough in age to socialize, after all. He left, they lost track of him, and Fina hopes that the Ramirez she knew isn't gone forever. After collecting the Blue, Yellow, and Purple Moon Crystal, they go and salvage Fina's ship from Deep Sky. They then head back to Crescent Isle to find Ramirez burning that down as well. After they fight, Ramirez takes the Moon Crystals in their possession.
Fina demands that Ramirez explain how he had changed like this so drastically. The Ramirez she knew was never like this. And boy, does he explain it to her. The Silvite Elders indeed told him to find all the Moon Crystals, yes, but it wasn't to save Arcadia. They had planned to call down the Rains of Destruction, and they were the ones who called down the Rains of Destruction all those years ago in the first place. Fina, in disbelief, tells him not to lie. Ramirez responds by saying that she was the one who was lied to, but he's not surprised. He continues on to say that he never wanted to call down the Rains of Destruction in the first place, but serving Lord Galcian gave him a new perspective. The Arcadians are nothing but shallow, greedy, petty scum that don't deserve to live.
The female Silvite only listens on in horror as Ramirez explains to her yet another fact that the Silvite Elders conveniently forgot to mention. All Silvites are born with a little piece of the Silver Moon Crystal inside of them. His proof is the Silver Moon Crystal piece inside his hand, which glows as he reveals it to her. But if that crystal piece is taken out, the person dies because that piece is directly connected to their life force. And with that, the location of Fina's Silver Moon Crystal piece is revealed as Ramirez telekinetically attempts to rip it out of her. He is foiled by Clara and Gilder who shoot a cannon at him (but misses because he dodged) and Fina can live another day.
The group heads to the Great Silver Shrine (after leaving their standby crew to fix things up in their now ruined base), where Fina was born, to warn the elders of Ramirez's sure to be inevitable arrival there as well as help Fina get some answers. It is there that Fina finally learns the truth. The Silvites used their Gigas, Zelos, to call down the Rains of Destruction, but Zelos was a monster. It had to be sealed up in Soltis and sent into Deep Sky. The Moon Crystals had to be gathered in order to break Zelos' seal and call down the Rains at will. They ask Fina why in the world she would side with the Arcadians, and she tells them off about how wrong they were to do this. Fina explains that she has met many Arcadians, both good and bad, but none of them deserved what the Elders brought on them.
Then Ramirez appears and slays the Elder Prime. He takes the Moon Crystal to Galcian, who says that he could never take Ramirez's Moon Crystal as he is much too valuable as a fighter. After Soltis is raised, Galcian dies, and Ramirez attempts to destroy the world, Fina is given a telepathic message from the Elders of their intention to crash the shrine into Soltis and destroy the shield that surrounds it. Fina can only watch as the shrine is engulfed in flames before shattering the dome. She goes with Vyse and Aika and a secondary playable character of the player's choice to confront Ramirez. Fina futilely pleads with him one last time before Ramirez does the unthinkable. He commits suicide by offering his moon crystal to Zelos, both awakening and merging with it to Fina's horror. After Fina and Vyse defeat Zelos, they see that something had crashed onto the deck of the Delphinus. That something is half Zelos and half Ramirez, and Ramirez looks marionette-like. After Fina and company defeat this form as well, Ramirez dies and leaves behind his Silver Moon Crystal. With Fina's consent, Vyse tells Ramirez to rest in peace and throws the Silvite's Moon Crystal into the sky as is Air Pirate custom.
As Arcadia rebuilds itself and Vyse's crew move on to their calling, Fina is seen in her new Air Pirate attire. Vyse and Aika express their surprise at the sudden change, but end up smiling only seconds later.
In the Japanese version of the game, she is voiced by Yui Horie. While in the English version, she is voiced by Julissa Aguirre.
In Valkyria Chronicles, she makes a guest appearance along with Vyse and Aika, but is not playable as they are. She takes the role of the unnamed medic who rescues fallen squadmates from the battlefield. She can be seen socializing with the aforementioned characters as well.
Fina also makes a brief appearance in the anime adaptation of Valkyria Chronicles in episodes eighteen and twenty-one.
When Fina joins Aika and Vyse, she will come at level one. Her skills in magic are by far the best out of the other playable characters. Despite her low level, she will probably end up being the first one to learn all of the magic in the game and have the most MP. Her S-moves are extremely useful as she is the only character that has S-moves that can heal other characters.
- Lunar Blessing (requires one moonberry to learn) - Fina gathers light in front of her as the moon rises in front of her. She says "Moons, give us your blessing!" as a green flower-like image appear underneath her and the party and a bubble forms around her and the party as well. This allows her and the party to regenerate two hundred hit points at the end of each round. The regeneration ability is lost when the character either faints or turns to stone. Benefits all members of the party. It requires twelve SP to use.
- Lunar Glyph (requires one moonberry to learn) - Fina places Cupil in front of her as he glows. Winds surround the selected target in a sphere as Fina looks into the sky. She commands, "Moons, petrify my enemy!" It only deals minor damage to the enemy, and it has a chance of turning the enemy to stone. Targets one enemy. It requires three SP to use.
- Lunar Cleansing (requires two moonberries to learn) - Fina says "Moons..." as bubbles appear around her and the party, then she finishes, "...purify our souls!" as a giant bubble encapsulates everyone and melts. It alleviates all negative effects except faint. It's the S-move equivalent of a curia crystal that benefits all members of the party. It requires six SP to use.
- Lunar Winds (requires two moonberries to learn) - Fina spreads her arms out as Cupil disappears. He reappears above and behind her and starts inhaling air. Fina orders, "Winds, cleanse the land!" as Cupil unleashes the wind he sucked up on the enemies. It removes any beneficial effect on enemies and does some damage. Targets all enemies. It requires six SP to use.
- Lunar Light (requires four moonberries to use) - Fina says "Moons..." as a barren land appears around her. She finishes, "...bathe us in your light!" and plants and flowers start to grow into the land and light floods in. It revives unconscious party members, restores everyone's hit points all the way, and removes any negative status effects. Benefits all members of the party. It requires eighteen SP to use.
Interestingly, all of Fina's S-moves have something to do with the moon...hence the "lunar" that precedes another word. Perhaps because Fina is a Silvite, she also harnesses the power of the Silver Moon in all of her S-moves.
Fina is seventeen years old. Probably due to her physical weakness, she dislikes exercise. Her hobby is taking afternoon naps, her strength is memory (this may contribute to why she is the most powerful out of all her allies in the field of magic; need memory to learn how to cast complicated spells so fast), and she likes flowers.
It is interesting to note that Fina has flowers in her room in the Great Silver Shrine. They did not actually grow there, however, as Fina explains. Cupil is a biological construct, so too, are the flowers in Fina's room. The sterile environment she lived in could never produce actual flowers.
A relief of Fina over the pond in Crescent Isle can be constructed by Izmael at Vyse's request. When drawing up designs for the flag of the Delphinus, Fina's design is that of a winged dolphin. In Fina's room at the Crescent Isle base, there is a picture of Vyse on her dresser.