In the anime and movie versions, Killua was born and raised in a family of assassins. I think his abilities and fast reflexes come from his family, the Zoldyck family.
So I would like to talk about the Zoldyck family.
Introduction to the Zoldyck Family
First of all, for Killua, there is Maha, who is his great-grandfather. Then there is his grandfather Zeno. Apparently he has a grandmother, but I don't know her name.
His father is Silva. His mother is Kikyo. There are 10 members in his family: the eldest son Illumi, the second son Milluki, the third son Killua, the fourth son Alluka, and the fifth son Karuto.
Abilities of great-grandfather and grandfather
Maha
His great-grandfather Maha is 98 years old.
He is the same age as Netero, the chairman of the Hunter Association.
Although he is old, he still works as an assassin.
Xeno
Has the ability to change forms of Nen.
By the way, Nen is the ability to turn the aura that comes from one's body into energy and control it freely.
He draws a circle around himself and emits a lot of aura to attack.
He has the ability to change the shape of a dragon using aura in several ways and attack over a wide area.
Parents' abilities
Silva
He has the ability to remove an opponent's heart without bleeding.
He has apparently fought Chrollo, the leader of the Phantom Troupe.
Platycodon
She always wears goggles, so even the family has rarely seen her face.
When she gets angry, she becomes very hysterical.
Brothers' Abilities
Illumi
The eldest son of the Zoldyck family.
Uses a Nen ability that uses needles.
Can stick needles into enemies and manipulate them as he wishes.
Usually has long hair and a quiet demeanor, but when he removes the needles, he becomes a completely different person.
Miluki
The second son, he is always playing games or in front of the computer. He has a manipulation-type Nen ability.
He has a grudge against Killua for various reasons, and they often clash.
Killua
The third son and Gon's first friend.
He can sometimes be a little cheeky in what he says.
He has the Nen ability to emit electricity from both hands and electrocute his enemies.
Alluka
She looks like a girl, but she is a boy.
When Alluka wants something, she will "beg."
If her request is granted three times in a row, she will no longer be Alluka, but will become a different person.
And if her request is refused four times, she has the ability to cause someone important to the person who made the request to die.
Karuto
Like Alluka, Karuto has a bob haircut and wears a kimono, so he is often thought to be a girl, but he is a boy.
He manipulates paper such as folding fans.
He attaches pieces of the paper to the enemy's body, listens to their conversations, and attacks them.
Summary
This time, I focused on Killua's family among the characters that appear in "HUNTER×HUNTER".
I was surprised at how many people there are in his family, and that each member of the family has some kind of ability.
I thought they were all the same, but since they all have different abilities, I think I got a glimpse of Killua's current strength.
The serialization has also started, so let's look forward to future developments.