Hunter X Hunter fans who have either read the manga or watched the anime adaptations are all familiar with the infamous group of assassins: the Zoldyck Family. They typically provide assassination services via various methods but occasionally grant favors to those they hold in high regard.
Throughout the series, Killua's father, Silva, and his grandfather, Zeno, are depicted as the heads of the Zoldyck family. Meanwhile, Killua has been shown to have the potential to surpass both of them.
Only a handful of Nen users have the ability to stand their ground against these assassins.
Note: This article reflects the opinions of the writer and contains major spoilers.
The Zoldycks are infamous
Even in a world of crime bosses and other assassins, the Zoldyck family is infamous because of their ruthless killing ability and overwhelming strength. They hold absolutely no regard for human life and view those weaker than them as lesser.
As seen in the Yorknew City arc, Illumi kills the Ten Dons, the leaders of various mafia organizations, without even batting an eye. During the Greed Island arc, Milluki kills 15 random people in order to get 15 billion jenny from his father.
They are just too powerful
Many members of the Zoldyck family go through incredibly dangerous training in order to become proper assassins. This training unlocks and harnesses the potential they each have, granting them unworldly levels of power. As a common trait, each member of this family has incredible physical strength, enhanced speed and reflexes, and high intelligence.
During the Chimera Ant arc, Cheetu taunts Zeno and tries to use him as a warm-up. Just as this is happening, Silva comes down from the sky and obliterates the chimera ant with one Nen-powered strike.
Another showcase of strength was when Zeno mentioned Killua's great-grandfather, Maha Zoldyck. According to Zeno, when Maha was younger, there was only one person capable of going up against him in a fight and surviving. That person was Isaac Netero. While we have never seen Maha in action, this statement speaks volumes to his strength since Netero was considered the strongest human Nen user prior to his death.
Despite all their strength, however, there are still characters the Zoldycks cannot hope to beat. So, instead of using brute force to take them down, they use their cunning intellect. A perfect demonstration of this is during Zeno's and Netero's assault on the chimera ants.
Zeno used a Nen technique known as Dragon Dive. Originally, the arrows were a single Nen dragon, so Pitou was expecting one full-powered attack. They were caught off guard when the Nen dragon split into millions of high-speed projectiles. Pitou's moment of hesitation gave Netero the opportunity to attack them and get rid of their chances.
Conclusion
To be considered one of the strongest in the Zoldyck family, a character is expected to possess a mastery of Nen and a terrifying presence.
Even the most powerful characters in the show have a difficult time keeping up with this family of warriors.