The Japanese prime minister. I hear a lot of bad rumors about him, and he is subtly depicted under other names in fiction as a horrible villain. Apparently crazier people in Japan even set themselves on fire in protest of his position.
But I don't know exactly what makes him THAT bad, if anyone knows.
The main thing is that he is a nationalist and most people (outside of Japan) don't like that. I personally don't take issue with it, he has every right to love his country and I see no problem with his desire to strengthen Japan's military given its aggressive/threatening neighbors.
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One thing I personally dislike him over is his support of revisionist history regarding Japan during WW2.
For example, downplaying (sometimes denying entirely) atrocities committed by the Japanese during WW2, such as the Nanking Massacre, the enslavement of Korean women as 'comfort women', etc... Once during a session of the Japanese Diet he questioned whether Japan had even committed acts of aggression during the war, arguing "the definition of aggression has yet to be established in academia or in the international community..."