So, it has been some time and I wanted to say a few things about the seemingly controversial episode no. 131.
People teased that moment for a long time in this thread as something that is possibly better than the Netero/Meruem fight, and I tend to agree: what a fucking game changer episode that was.
Granted, the Netero/Meruem episode had the great fight between super human and super ant, but this episode 131 felt like a huge long-awaited payoff. I watched the episode with my younger brother, and after Gon called Pitou a liar and the whole transformation began our jaws were on the floor the entire time. I remember us screaming when Pitou noted than Gon was on the same level as the King (probably pre-absorbtion/rebirth).
The whole presentation did a perfect job of showing Gon diving into a dark abyss, from the music to the black/white animation when he transforms - and man, that voice actor is doing a killer job. We were kind of baffled why his hair was so long at first, but I kind of thought that he must have aged a lot (!) on the spot and that his aura must be so strong that the hair is pointing towards the sky like a black pillar of doom. It might be a little DBZ homage as well.
The confrontation between Gon and Pitou was brutal, from the beginning to the end - that wasn't a fight, it was a goddamn massacre from the first second on, and I kind of appreciated at first until it became sadder and sadder. Watching him kill Pitou with basically one kick and then going further by smashing her skull with multiple Nen-boosted punches was not only brutal but also heartbreaking because it makes so clear how helpless Gon is when he's confronted with defeat since physical violence is the only solution he sees at that moment.
And the final moment with him jumping up towards sky, the music kicking in and him grabbing his cut-off arm only to throw it down like a thunder was incredibly well done. Seriously, I wished the music of that episode was available already. The whole Gon-san sequence gave me wet eyes; something that almost never happens with most media that I consume.
One of the best episodes in the entire anime, period. And to those who criticize that it feels like Deus-Ex-machina: bullshit, everything you need to know about what happened to Gon can be explained with what you learn in the anime, it's all there. You can disagree with Togashi's solution for being too exotic to grasp, but that's the entire point of the show in the first place, right? And we'll probably get more explanation anyway after the King situation is cleared.