Remember this scene? I remember watching it and wondering why his father seemed so benevolent and just despite being the head of a notorious assassin family. It confused me by how accepting he was of letting Killua leave, so when he said this line I knew something was up and going to come back to us.
And this was it. The moment when Bisky states that Killua is essentially a coward and if he doesn’t change he will eventually betray his best friend in the final hour. And so he decides….
Which is why his fight with Rammot is so compelling. Killua is literally the best because he finds inner strength to protect Gon despite his cowardice and instincts of self preservation. He actually learns self sacrifice and finds the will to fight for the sake of Gon, who he cares very deeply for. Are people still seriously debating if these two aren’t perfect together?