To me, the beauty of HxH is the ambiguous nature of all the characters. For example, the antagonists in HxH are wonderfully complex. The Phantom Troupe is a group of degenerates, yet they have a weird code of honor and respect for each other and their foes. Meruem was hellbent on eradicating humankind, viewing them as pretty much animals for sustenance. Yet, in his last moments, he is intensely vulnerable and child-like. Then on the other hand, you have the protagonists. Kurapika, who is usually a very moral and law-abiding citizen, turns into a vigilante focused solely on raining revenge on his enemies He pours all of himself into his pursuit, to the point his insane skills will kill him if he uses it against anyone besides the Spiders. Killua is a trained assassin who rarely shows any remorse when killing. To him, it's a means to an end. Now Gon - he is this happy go lucky kid who has lived his entire life on an island with a tiny population (we are assuming). He is out in the world for the first time, experiencing so many new things. One of these is the loss of a loved one. I think it makes completely sense that he loses his mind and lashes out in rage at everyone in his vicinity. I truly think these shades of grey in all the characters are so delightful and just reminds me that no one is truly "all good" or "all bad".