>>50063877>why would he kill N?Simple, N discovered the truth. Before his fight in USUM, Ghetsis talks about how humans are easier to control than "a freak without a human heart" thanks to humanity's predictable ambitions.
In Generations episode 15, Nate doesn't set off to fight Ghetsis, so N has to go alone, when Ghetsis wins he orders Kyurem to "freeze the freak solid", the only reason why N doesn't die right there and then is because Hilbert returns with Zekrom.
The thing is, once Ghetsis has N's dragon, no one can stand in his way because N already made everyone willingly release their Pokemon and Team Plasma released all the Pokemon that were in PCs, very few people would have Pokemon and those who do are outnumbered, outgunned and outlawed. Ghetsis doesn't have to hide behind an excuse anymore, he can be as publicly as cruel as he wants to be.