Amon is a minor villain in the Fist of the North Star spinoff/prequel, Legends of the Dark King.
He was the founder of the Cassandra Prison. Amon fortified the city with traps to keep invaders out, but many of his own soldiers including his son, Zenos were killed by the traps.
When Raoh comes to the prison city to take it over, Amon becomes aware of his presence. Seeing how they are in the same room as him, Raoh points out the old man he met outside is Amon's brother.
Amon then attempts to kill Raoh with his Taikyoku Ryuken technique, Hiryuu Genbu, but Raoh deflects the attack. Seeing that he has lost, Amon activates a lever making the room shake violently in an effort to kill Raoh and his party. Just as he says he'll have Zenos succeed him, Souga warns his son was killed by the traps as per the message of the elder.
Having realized the truth, Amon believes them before a part of the ceiling crushes Amon to death. His position is then taken over by Uighur.
Powers and Abilities
Using Taikyoku Ryuken, Amon's only known usage of the technique has him fire dragons of energy.