Thalassa is Magnifi´s daughter and a magician assistant from the Gramarye Troupe and she can use the Perceive System.
Thalassa was raised as Magnifi's daughter, and worked as a magician's assistant to him and his pupils. When Thalassa was young she left the Gramarye troupe to marry another performer, and by him she had a son, Apollo. But only a year later her husband was killed on stage. She gave the infant Apollo one of her bracelets, and left him to return to the Troupe (where she left him and with whom is never stated). She then married Zak, and they had a daughter, Trucy.
A few years later, Thalassa was practicing a trick with Zak and Valant that required the use of prop pistols, and was shot. Her father quickly took charge to cover up the accident, to protect the Gramarye name. Zak and Valant believed Thalassa to be dead. But somehow she survived, and in a strange twist of fate ended up in the small European nation of Borginia. She lost her memory and her sight from the trauma, and to make her living began singing in a small restaurant, accompanied by young Machi Tobaye. She stayed there until "discovered" for her talent, and toured the world as Lamiroir.
After the case case 4-3, Lamiroir recovers the sight and the memory.
- Thalassa is the name of a sea goddess in Greek Mythology. Gramarye comes from Grimoire, and ancient book of magic.
Yuumi (優海) contains the kanji of "sea".