The World's Most Notorious Assassins
Mountain-Dwelling, Multi-Generational, Fully Staffed
The Hierarchy
Zeno is the grandfather and the family's most experienced living weapon, Silva is the current active patriarch running operations, and their children exist somewhere between family members and assets in training. Killua, the third child, is positioned as the heir apparent, which the show treats less as an honor than as a life sentence he never agreed to.
Illumi's Role
SPOILER!
Killua's eldest brother functions less as a sibling than as quality control, an elite assassin whose entire relationship with Killua is built around keeping him aligned with the family's purpose. His disguise as "Gittarackur" during the Hunter Exam, distorting his own skull with Nen needles to hide his identity, is the first hint of how far Illumi is willing to go to monitor his brother without being seen doing it.
How Killua Was Raised
SPOILER!
Poison immunity training, psychological conditioning, and physical torture starting essentially from infancy, all delivered as ordinary parenting inside this household. By the time Killua reaches the Hunter Exam, ripping a man's heart out without hesitation isn't a special skill he's proud of, it's just Tuesday. Everything about his friendship with Gon reads as urgent specifically because it's the first relationship in his life that doesn't come with an assignment attached.
The Estate Itself
The Zoldyck compound is built to kill uninvited guests before they get anywhere near the actual house, complete with trained gatekeepers, a testing gate rigged for anyone who can't prove they belong, and staff who treat lethal force as routine facilities management. Gon, Kurapika, and Leorio don't break in so much as survive the attempt long enough to be noticed.