|Race||Third Generation Reyvateil/Human|
|First Appearance||Ar tonelico ~Arpeggio~|
- "The Reyvateil are suffering… I can’t just abandon them…"
Sonnet is the heroine of the Ar tonelico sidestory manga, Ar tonelico ~Arpeggio~. She is a Third Generation Reyvateil, born in the city of Platina. Unable to ignore the suffering of the Reyvateil, she descends from Platina in order to search for a Hymn Crystal that would halt the Reveris disease, and to be brought back to Masticus afterwards. Unlike the normal Third Generation Reyvateils, she possesses a Hymn Code, thanks to the fact that she inherited the Spectrum Gene of an ancient Pureblooded β-type Reyvateil. The songs she uses for her Song Magic and normal singing have the recurring themes of birds and wings.
She wasn’t even old enough to understand what had happened when she lost her parents, and was taken in by Masticus. She became devoted to him and obeyed all of his orders without questioning. It was because of Masticus' orders that she went to the Lower World to seek out the Hymn Crystal "Soporific".
She appears before Espada and Adagio to thank them for stopping a rogue Reyvateil, and then asks Espada for his sword, noting it has the Hymn Crystal she was looking for incrustated into it. He refuses after noticing she's a Reyvateil and she proceeds to attack them until she passes out and is treated by Kauron for fatigue. After Espada storms out, she and Adagio learn from Kauron how his parents were killed.
They travel to the Airport City Nemo where they meet Adagio's sister, Andante. Once Adagio is dragged off, she stops some Tenba members from attacking a young Reyvateil and sings a song. The area is attacked and they chase after the culprit, learning that it was Adagio's doppelgänger, who showed them a little of the past story of the world. The group then leaves to eat, but she leaves to go outside, where she talks to Masticus through a earpiece. She then decides to take the sword for him. Nemo is attacked and they head towards it.
After suppressing more Reveris-outbroken Reyvateils, they meet with members of the Church who offered them a chance to rest. She passes out and later that night a surge woke her up. They go to the source of the surge only to find Espada fighting with Kauron, and after getting away she heals him, and she makes it clear that he's a Virus and that his true body is in Platina. She tells him that she would like him to help stop Kauron but when he refuses, she goes on her own while Adagio holds Espada back. She, along with a knight, fight the Reyvateils until she uses a song to temporarily shut down their connection to Ar tonelico. Kauron then attacks her, but Espada saves her, giving her a lecture about thinking of everyone else before herself at the same time. After Kauron dies, she apologizes as she takes away Espada's sword, and leaves for Platina.
Back in Platina, she meets with Masticus and hands over the sword to him. She later discovers that he created the Reveris virus and runs out before realizing that she has nowhere else to go and agrees to follow him. By the time Espada reaches her, an illusion containing her last hopes disappears, leaving behind her necklace. At this point, her body was completely consumed by Reveris, turning her into a Virus.
Masticus appears with Sonnet's body, stating that Reveris has taken over her. As Espada and Adagio pursue them but are lost in the process, Sonnet's pendant guides him to her. However, under Masticus' orders, she attacks him and Adagio. Unable to kill her, she launches a fatal spell. At the last moment she stepped in and intercepted the attack and cast two spells to protect and heal him and then she died.
A New Life
Using the reincarnation spell and Mea she was revived as a human but she no longer had any memories of her past. Shurelia then took her into Platina for safety. Years later while singing in Nemo, her reincarnated form meets Espada and Adagio.
- Her Install Port is on the back of her hand.
- She is one of the few Reyvateils who possess a Hymn Code. They make roughly a 10% of the total Reyvateil population of Sol Ciel.
- She is the only character in the series to go from Reyvateil to Human.
- Sonnet appears in one of the chapters of the Ar tonelico II manga, as an illustration to accompany an explanation about Reyvateils.