Lavi is a monster user that travels alongside Keel, Mippy and Happy in search of her teacher, Siva.
Lavi comes from a musicial family with ancient noble roots. When she was younger, she managed to play a melody, that her father composed, on the piano even though she was never taught how to play. As a result, she was considered and praised by her father as a gifted child who had inherited her family's musical talent. Despite having a good relationship with both her parents, Lavi's true dream of becoming an adventurer and a magic monster user was vehemently rejected by her father, forcing her to run away from home.
Following these events, Lavi has lived a "street lifestyle" with her pig monster Mippy (it is unknown when or where she had befriended it), playing melodies on the streets in exchange for money. But after meeting Keel and Blue, she now travels with them to find the "4 Sacred Treasures" in hopes that they will encounter Siva, her teacher and savior, who has been missing for 2 years. It is important to note that little is known about when Lavi had met Siva or how and what he saved her from, but according to Lavi, he had taught her many things including the various music she now plays to aid her friends in battle.
Although there is little information on the creator's (Kenshiro Sakamoto) inspiration to create Lavi, there have been noticeable similarities between her character and those from other series, particularly Lucy Heartfilia from Hiro Mashima's Fairy Tail. Like Lucy, Lavi comes from a wealthy family and ran away from home to pursue her dreams. They both have blonde hair tied to the side (albeit in a slightly different fashion) and use monsters ( Celestial Spirits in Lucy's case) to fight for them.
Lavi has long blonde hair (and a couple of black streaked hair) tied to the side with yellow eyes and is never (or rarely) seen without her magical guitar. In addition, her attire seems to change from time to time, but she mostly wears her signature clothing being a white and pink hoodie with a black and red checkered skirt and stripped stockings.
Lavi is a kind, bubbly and energetic girl who shows deep trust and care towards her friends, including her monster, Mippy. After meeting Keel who had verbally bashed monster users for using their monsters as tools to fight for them, Lavi retorted stating that her monster is not a pet but a companion. She had proved this when she protected Mippy against an attack from a King Lizard despite getting hurt in the process. She also plays the role of the peacekeeper, often trying to calm down Keel and Blue whenever they engage in their silly feud, even sometimes with forceful means (i.e. punching Keel in the face). No matter how insulting or unfriendly the person may be, Lavi will always try to find the good in everyone.
Lavi is first seen performing for a small crowd in the middle of town when Keel rampages through the city streets yelling out her name. After identifying herself as Lavi, he introduces himself and immediately asks her if she knows anything about Siva, adding that the man stole something very important from him. Suddenly a group of lizardmen appear and attack the towns people, prompting the mayor's hired adventurers to eliminate them. As Lavi and Keel dodge the lizardmen's attacks, the latter inquires about Siva's location to which Lavi replies that she has no idea since he's been missing for 2 years. Upon learning this, Keel, in a fit of rage, knocks out the lizardmen single-handedly. To help, Lavi plays the "calm down" melody (look at description below) to send them back to the forest and away from town. As the town's police rejoice, Lavi informs them that the monsters attacked them most likely on someone's orders, probably the C-Class monster Boss Lizard, hence they may still return. The mayor's adventurers then volunteer to get rid of the threat (but not without compensation), and ask if Lavi and Keel would like to join their team to which the former gladly accepts. Later, Keel passes Lavi's hotel but stops when he hears her play a familiar tune.
The next day in the forest, Keel asks Lavi about the melody she played the previous night to which she answers that its the music her savior played. Just then, they notice a lizard monster and follow it only to unexpectedly encounter an A-Class monster, the King Lizard. Despite the fear the adventurers expressed, Keel, unfazed by its high rank, strikes the monster with a strong punch but is easily knocked back. After Lavi's "calm down" melody had little effect, she decides to play the melody "Fire Soul" to boost Mippy's fire breath attack. As Keel watches, he asks Lavi how the King Lizard isn't being affected by her melody and she replies that Mippy has a contract ring that allows her melodies to only affect him. Soon after, Mippy is knocked to the ground by the monster prompting the adventurers to flee for their lives, leaving her and Keel behind. As the King Lizard was about to strike Mippy, Lavi shields him and takes the hit. When asked by Keel why she did that, she replies that Mippy is her comrade and that she would never betray him. After failing to hold back a direct hit from the monster, Keel is given a contract ring on his request and tells Lavi to play her melody. Upon doing so, Keel's arm transforms into a Dragon Ape arm and reveals that Siva forced him into a human form 3 years ago. Lavi then recalls his words when they first met and realized that he was the monster that Siva supposedly killed 3 years ago, the S-Class monster, Dragon Ape. With the power of his arm, Keel defeats the King Lizard.
As the two walk back to town, Lavi learns that the collar on Keel's neck forces him to remain in a human form and that the music she played partially released the seal. When he asked if that was Siva's melody since he played it when he placed the collar on him, Lavi answers that Siva was her teacher. After stating that she didn't know nothing of Siva's whereabouts, Keel proposes they form a team to search for him to which Lavi and Mippy joke as a bad idea.
After packing, Lavi, Keel and Mippy visit Siva's rundown home to search for clues when they find one of his manuals that contains very detailed information on every type monster he had encountered, including the Dragon Ape. As Lavi flips through the pages, she stumbles upon the circled phrase "The 4 Sacred Treasures" which, according to legend, are treasures that when collected together, grant the wielder God's powers. With the possibility that Siva went in search of them, Lavi proposes they travel to Shiton to find information on the whereabouts of these items.
At the carriage station, Keel starts to pick a fight with a man who ends up riding along with them. After an exchange of insults between him and Keel, Lavi and Mippy, they all make amends and the man introduces himself as Blue. However, they are suddenly attacked by a gang of Ogre Dragon Thieves.
Lavi is a monster user who uses her magical guitar to play melodies that can control monsters and/or enhance a monster's fighting capabilities through a "contract ring" (which only allows the music to effect the monster that wears it). Currently, Mippy, Blue and Keel wear a ring for Lavi's melodies to increase their powers.
|"Calm Down"||This melody causes monsters to become quiet and calm down as the name implies.|
|"Seal Melody"||A lost melody that when recited, can lift any seal placed on a monster. Lavi can only play a small part of it, allowing only Keel's right arm and tail to revert back to its original form.|
|"Fire Soul"||This melody increases the power of a monster's fire-based attacks. Lavi frequently plays this to enhance Mippy's fire breath in battle.|
|"Fairy Talk"||This melody is a healing song and is the first magical melody that Siva taught Lavi.|
|"Fairy Sleep"||This melody causes monsters to fall asleep.|
|"Sylph Wind"||This melody increases the power of a monster's wind-based attacks.|
|"Winning March"||Any monsters that hear this melody will power up and become stronger. However, according to Shiro, its effect will only correlate with the trust between the user and the monster. Hence, if there is little trust between them, the melody will be ineffective which explains why it did not work on Kurokiri.|
|"Aqua Drive"||This melody boosts the power of a monster's water-based attacks.|