In the following years, Fermet tortured his ward, Czeslaw Meyer, until the boy devoured him at an unknown time. He survived not only that devouring but another one by a fellow immortal alchemist, and would go on to stowaway aboard the Flying Pussyfoot in 1931.
Fermet has brown hair with long bangs that cover his eyes. Beyond this feature, his appearance is described as nondescript. His hair is shoulder-length in the 1700s and 1935, and cut short in December 1931.
(To be expanded on)
To most people, Fermet presents himself as a humble, thoughtful man who is nothing but gentle toward others. His true nature is anything but kind: he is a cruel sadist who delights in bringing pain to the innocent and 'pure'. While he relishes the physical pain he can inflict upon others, where he truly excels is in causing others mental anguish.
He has demonstrated enormous patience when it comes to his plans, such as cultivating a years-long friendship with Jean-Pierre Accardo to not only manipulate him for his own benefit, but to see the horror on his face at the realization their friendship was a lie.
(Will be rewritten) Fermet was the last student of Czeslaw Meyer's grandfather, and already knew Begg Garrott and Dalton Strauss before the events of the series, having known the former from the same teacher and having met Dalton at least once already.
Though not stated explicitly, it is possible that Fermet was responsible for the deaths of Czeslaw's grandparents and parents. While he does not appear personally in this book, he is mentioned as "Lebreau," (his first name) first by Dalton to Zank Rowan and Denkurō Tōgō as a "Rookie". Begg later tells Maiza Avaro that Fermet will be looking after Czeslaw Meyer and that he'd be helping him.
Fermet appears at a party in the Avaro manor as the guardian of six year old Czeslaw Meyer, the son of Fermet's recently deceased alchemy mentor. Fermet offers to introduce Maiza and Jean-Pierre Accardo to Dalton Strauss, and the four of them meet up with Begg Garrott on the way to the Third Library. There, they witness Dalton's death and regeneration—and Maiza becomes Dalton's pupil on the spot. Fermet continues to play a part in the events by telling Jean about the childhoods of Huey Laforet and Monica Campanella; Jean writes two plays based off Fermet's tales and has them performed in Lotto Valentino, unwittingly causing severe damage to Huey and Monica's relationship. Monica is later murdered by Fermet.
In this book, it is revealed that Fermet was a stowaway on the train like Rachel, though he has no impact on the events that take place during this arc.
Despite having apparently been eaten by Czes and another alchemist who was later devoured by Szilard, Fermet remains alive in the twenty-first century. He is revealed to be the Copycat who attempts to recreate the Flying Pussyfoot incident on board the Entrance and Exit, and his full name is confirmed to be Lebreau Fermet Viralesque.
Fermet is an extremely talented actor, strategist, and manipulator, even earning Dalton's praise as a genius. He managed to convince everyone in his workshop and Lotto Valentino that he was a very kind person, all the while having been behind the tragedies that occurred in the early 1700s.
He seems to be well versed in torture as seen with what he did with Czeslaw Meyer, however his knowledge doesn't seem to include more advanced levels of pain as noted by the Rail Tracer.
On the Advena Avis, Fermet drank the Grand Panacea and obtained true immortality, meaning that he cannot age, fall ill, be permanently injured, or die via conventional means. The only way to truly kill an immortal is for another immortal to devour him or her, though Fermet appears to have circumvented this rule at least twice.
(All to be rewritten)
Czeslaw Meyer: Sometime after they became immortal, Fermet began to "experiment" on Czeslaw by torturing him, claiming that this was all in the name of determining the limits of immortality; Czes reports that Fermet's memories show that he was actually motivated by pure sadism. This went on for an unknown number of years before Czes managed to slip his right hand out of his bindings and devour Fermet. However, in the 2002 novel, he somehow survives this devouring and lives till the 21st century.
Firo Prochainezo: Firo has the memories of a man named Lebreau who was devoured by an alchemist who was devoured by Szilard, who was later devoured by Firo. Somehow, Fermet was able to escape being devoured by this alchemist, although Firo still retains some memories of "Lebreau" even though he is still alive. Firo tries to avoid these memories, and states that he will endeavor to not become like Lebreau.
- His name is pronounced as Fair-May in the dubbed anime but Fair-mate in Japanese.