Killua is one of the members of the Zoldyck family and a trained assassin with phenomenal skills as a Hunter. Being a close friend of Gon, he's is also one of the main characters of the Hunter x Hunter series.
Killua is said to hold tremendous potential, comparable to that of Gon himself. Over the course of time, he's only gotten stronger and by the end, he'll be one of the strongest in the series. Here are 5 Hunter x Hunter characters that Killua will surpass and 5 that we won't.
10 Will Surpass: Silva Zoldyck
Silva is the current leader of the Zoldyck family and one of the strongest Hunters in the series. He's fought against the likes of Chrollo and other members of the Phantom Troupe, implying that he's a capable fighter.
Silva acknowledges the potential that Killua carries and even understands to some extent that his son could end up becoming stronger than him, which is most likely going to be the case.
9 Won't Surpass: Chrollo Lucilfer
Chrollo is the leader of the Phantom Troupe who hails from Meteor City. He's an extremely powerful Nen user who has the power of Skill Hunter at his aid. Chrollo was able to fight against both Silva and Zeno Zoldyck at the same time, implying that he was superior to both, individually.
Furthermore, there is room for Chrollo to get even stronger, meaning by the end of the series, Killua might not have surpassed him after all.
8 Will Surpass: Illumi Zoldyck
Another member of the Zoldyck family, Illumi is a tremendously skilled assassin who specializes in Manipulation based techniques. Even Killua fears his powerful aura and his killing intent, which says a lot about him.
Although Illumi is stronger than Killua at the moment, come the end, Killua is likely to surpass him and become the strongest member of the Zoldyck family by far.
7 Won't Surpass: Meruem
Also known as the Chimera Ant King, Meruem was the strongest known character in Hunter x Hunter. His powers were such that even Netero and all the other Hunters in the world couldn't stand up to him.
Meruem was able to defeat Netero without much trouble and even his strongest attack barely scratched him. Undoubtedly, Killua will never reach the same heights as Meruem.
6 Will Surpass: Hisoka
Hisoka is one of the strongest characters in Hunter x Hunter currently, comparable to the likes of Chrollo himself. He wishes to fight against both Gon and Killua one day when they're finally at their strongest.
It goes without saying that Hisoka will end up clashing against Killua at some point in the future, and we'd like to believe that the latter will be powerful enough to take him down and prove that he's stronger.
5 Won't Surpass: Gon Freecss
Gon is the main protagonist of the Hunter x Hunter series and Killua's best friend. Just like Killua, Gon is known to carry tremendous potential that may even exceed that of Killua.
The two often progress together and are relative to each other, in terms of power. It goes without saying that Gon will either be an equal to Killua or just a tad stronger than him by the end.
4 Will Surpass: Menthuthuyoupi
Menthuthuyoupi was a member of the Royal Guard of the Chimera Ant King Meruem. Born with exceptionally powerful Nen, Youpi could barely be taken on by any Hunter. In fact, a collective effort of several powerful Hunters wasn't nearly enough to keep him at bay.
Although Youpi was tremendously powerful, the fact that Killua has limitless potential means that he will eventually surpass him as a fighter.
3 Won't Surpass: Maha Zoldyck
Possibly the strongest member of the Zoldyck family to ever live, Maha is said to be a rival to Isaac Netero himself. In fact, it was said that nobody who fought him lived to see the next day, except for Netero.
Interestingly, Maha is the only Zoldyck family member known to be primarily an Enhancer. The fact that he was on the same level as Netero means that Killua might struggle to get on his level or surpass him.
2 Will Surpass: Neferpitou
Neferpitou was one of Meruem's Royal Guard, and just like the other two, they were devoted to him. Pitou was born with magnificent Nen, powerful enough to kill someone like Kite without much trouble.
However, Pitou fell to adult Gon quite easily, which means that Killua, towards the end of the series, will likely be much stronger than Pitou as well.
1 Won't Surpass: Isaac Netero
Netero was the former Chairman of the Hunter Association and the strongest known Hunter in the entire series. He was tremendously skilled as a fighter and his training led to him surpassing all the limitations of a human's power.
Netero was able to put up a fight against Meruem, which nobody else could've done at the time. For Killua, surpassing him is a rather arduous task that he might just not accomplish after all.