Dr. Giovanni, alias "Plague Mask," serves as a former captain of Special Fire Force Company 3 and clandestine operative for the White-Clad. His eerie visage features a stitched plague doctor mask, black top hat, and white scarf that transitions into a cross-patterned trench coat upon fully joining the cult. Over years, his body integrates mechanical augmentations and insectoid traits, culminating in a fire-resistant swarm governed by a central robotic core. Born into a lineage co-responsible for constructing the Amaterasu Generator alongside the Joseph clan and Haijima Industries’ founders, Giovanni inherits a mission to ensure the Cataclysm’s arrival. Prolonging his life through parasitic bug-mediated consciousness transfers into younger hosts, he discards humanity to witness Adolla’s global consumption. Initially apprenticed to Vulcan Joseph’s grandfather, he betrays the family after their spontaneous combustion as Infernals, aligning with Haijima Industries to advance his agenda. A Second Generation pyrokinetic, Giovanni manipulates external flames to operate mechanical arms, wired appendages, and concealed weaponry. Adolla-linked fire-bug experiments grant him compound eyes, pheromone detection, and swarm dispersal to evade harm. He perfects consciousness transference via parasites, hijacking bodies like Yū’s and imprinting hosts with stitch-like scars and disheveled hair. Giovanni balances cold scientific inquiry with merciless pragmatism. Posing as a loyal Fire Force captain, he masks zealotry for the Evangelist and contempt for ordinary humans. Upon revealing his allegiance, he exploits allies as pawns, mocks adversaries, and revels in ecstatic fervor during Adolla experiments, deeming lives expendable for the Evangelist’s vision. His machinations focus on seizing the Amaterasu Key guarded by Vulcan’s family. After ambushing Vulcan’s workshop, he tortures Yū, destroys sentimental heirlooms, and claims the Key. Subsequent schemes lure Fire Force members into traps, deploy Adolla-linked insects, and culminate in a battle against Shinra Kusakabe, where he touts his insectile evolution. In his final gambit, he hijacks Yū’s body to unleash catastrophe but meets annihilation via Arthur Boyle’s flames. Degrading into a swarm of non-human insects, Giovanni embodies his rejection of mortal form. His legacy spurs Company 3’s defection to the White-Clad and fuels conflicts steering the world toward the Cataclysm, securing his infamy as a linchpin in the war for Adolla’s secrets.