Alberic Gillette is a knight of the Kingdom of Vemac, operating under the Kleeman Agency's Post-war Reconstruction Implementation Agency. He commands the Gillette Corps, charged with preserving peace after the war against the Gaz Empire. Initially idealistic, he holds firm convictions about justice and order in the postwar landscape. His personal history remains largely undefined, though he actively engages in reconstruction efforts.

Gillette pilots the advanced mechanical carriage "April" for covert missions transporting sensitive assets. During one such assignment to Delsorant, he voiced concerns that daytime movement risked attracting unwanted scrutiny. As a leader, he exhibits charisma, earning steadfast loyalty from subordinates Viivi Holopainen, Nikolay Autotor, Mattheus Callaway, and Zita Brusasco. He maintains a strictly professional dynamic with Viivi, oblivious to her romantic attachment to him.

A profound transformation follows Guy's life-saving intervention. This event reshapes Gillette's demeanor into silence and ruthless combat efficiency. Guy discerns an inherent unsuitability for peace within him—a subconscious craving for war's rigid structure and purpose. This shift culminates in a violent clash where Viivi, forced to choose between his life and Nikolai's, severs his hand to halt his attempt to kill Nikolai.

His combat expertise centers on longsword mastery. After his psychological fracture, his fighting style turns markedly merciless, mirroring the internal conflict between his founding ideals and his latent affinity for warfare.