Charon was the main antagonist of the last three volumes of the Pokemon Diamond and Pearl Adventure! manga. He was the leader of the "Neo Team Galactic" organization which was established after Cyrus, Mars, Jupiter, and Saturn redeemed themselves.
In the manga
Charon made his first appearance in the manga by attempting to suicide bomb a stadium full of innocent bystanders. When that failed, he kidnapped Cyrus, and he tried to murder two of the top officials of the organization who were researching the whereabouts of the previous leader.
Charon was power-hungry and he planned on controlling the world by selling Legendary Pokemon to the highest bidder. He also plans on conquering Kaisei so that he could enter into the Distortion World in the hopes of acquiring Giratina. He first appeared as a silhouette in "Surprise Visit from Hareta's Father!" and he was also shown battling for the first time in "Charon Must Be Stopped."
In the manga, Charon values money above any other form of life, and he certainly has no qualms about murdering innocent people if it were to come down to that point.