Antonio Luini, called "The God of Death," is a middle-aged child trafficker supplying indentured chimney sweeps in 19th-century Milan. He bears black hair, black eyes, a beard, and a prominent scar near his left eye, consistently dressing in black attire—hat, jacket, pants, and shoes.

Luini targets impoverished villages like Switzerland’s Sonogno, exploiting families in extreme hardship. He manipulates and coerces parents into selling their children through monetary contracts. When Romeo’s father refuses, Luini deliberately burns their cornfield, causing the father’s blinding head injury and crippling the family financially. Luini then secures an agreement with 11-year-old Romeo for 25 francs, guaranteeing medical treatment for the father.

Transporting multiple children to Milan under brutal conditions, Luini confines them in a basement and forces a crossing during a violent storm. Many children drown, but Romeo rescues Luini from the lake. In Milan, Luini sells the children: Romeo to Marcello Rossi and Alfredo to the abusive Citron.

Luini’s actions propel the narrative’s early events, though his role recedes as focus shifts to the Black Brothers' resistance.