Both were burnt to near death for no good reason.
Both cover up there burns (though Amon does a far better job of this).
Both want revenge for what happened to them.
Both wish to rule the world.
Both are voiced by Steven Blum.
However there goals are the complete opposite. Amon wants to create equality while Shishio wants a world meant for the strongest and only them.
Now who would win in a fight?
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Burning Spies is one of my Specialties!