He seems to be cut from quite a different cloth from Knuckle, and has correctly guessed that Knuckle has taken a shine to the kids – and it’s clear he intends to act on his own as soon as Knuckle sends them on their way, beaten, to keep training for another day. What we know of course is that the both of them are relentless and learn with astonishing speed (and as Knuckle observes, they take huge leaps of confidence with every threshold achieved) but the wild card is (presumably) Shoot McMahon, the other assassin Netero referenced. If this one isn’t as tense as some of the others because we know neither Gon nor Knuckle would go so far as to kill the other, the action itself is still spectacular – and it proves that even two-on-one, Knuckle is more than a match for the boy prodigies. Gon’s decision proves to be as fortuitous for us as it does for Knuckle, because it gives Madhouse a chance to show off still more of the astonishing “Sakuga” animation that’s marked every fight in this series. Fortunately Gon is as sporting as he is strong and not only declines to take a token he hasn’t won in a fair fight, but drags Knuckle back to the hotel to sleep it off and eat a hearty breakfast (I suspect Kil would have gladly taken the token if it’d been up to him, but Gon and Knuckle appear to be soul-mates). But will power is Gon’s strength even more than Nen, which Knuckle finds out to his great discomfort.
In this case it isn’t simply a matter of size but the fact that the kids are clearly exhausted – Biscuit has sent them to him immediately after they’ve utterly drained themselves finally mastering their three-hour Ren exercise, with instructions on how to effectively cheat and rig the contest in their favor. Knuckle makes the same mistake most make – he takes a look at the boys and radically underestimates their strength, to the point where he offers to let Gon punch him as many times as he wants to try and make him move a single step, after which he’ll surrender his token. In purely practical terms, Knuckle represents an obstacle for Gon and Killua, plain and simple – each has something the other needs to proceed – and sentiment (Gon clearly comes to like him quickly and vice-versa) can’t change that fact. Togashi has created an utterly fascinating conflict here, even by his lofty standards.
But for the most part they’re more than anything else a rival – a rival for humanity’s place at the top of the evolutionary totem pole, and one who uses humanity’s best and worst traits as part of their arsenal. Their goals put them fundamentally at odds with humans, we find their actions horrifying (from our perspective they certainly are), and there are those among them who behave cruelly for the pleasure of it – a trait they mostly inherited, it must be said, from their human genes. As I’ve said before the Chimera Ants are fundamentally different from the likes of the Phantom Troupe or Genthru in that their basic motivation is simply to survive and expand their species. It’s easy to mock Knuckle’s view about the ants as naive and it’s likely to be proved wrong, but as with Morel’s lecture to Killua I don’t believe this is something Togashi intends to be viewed as a black and white, right or wrong issue.