Alderp is a corrupt noble who is the arch-nemesis of the noble crusader Darkness and a major antagonist for the first half of the series.
Alderp's luck, perverseness, and cunning are equal to or possibly greater than Kazuma's own. In many ways, he is like the evil version of Kazuma, that does not care about his comrades or friends. He is seen has very corrupt and will use foul-play to get what he wants. This is seen in Kazuma's trial where he uses his position to have the judge call out Kazuma as guilty. When Kazuma calls out foul-play, Alderp simply states that Kazuma is just a worthless adventurer.
Alderp is also known to marry any woman he likes through force, then divorcing them when he is no longer pleased by them, due to his deal with the devil Maxwell, none of the women he previously married press any charges against him.
Alexei Barnes Alderp was a powerful noble who governed over the region of Axel. Ever since his wife passed away, Alderp has been obsessed with the fair noble lady Dustiness Ford Lalatina, although all of his proposals and advancements were rejected due to their hefty age gap.
One day Alderp obtained a divine relic which summoned random monsters. The first monster to be summoned was a devil named Maxwell, which Alderp bound to his service. The devil had the power to alter the memories and manipulate the minds of people, a skill that Alderp made great use of. Fortunately for Alderp, Maxwell suffered from short-term amnesia, and so forgot any previous deals he made with Alderp, this meant that Alderp didn't have to pay for any of the tasks he had Maxwell perform.
Alderp eventually came to possess another divine relic which could swap the bodies of two individuals. With this information, Alderp adopted a boy named Walther so he could take over his young and attractive body if he needed to.
Trial of Satou Kazuma
One day, when Alderp was meeting with Maxwell in his basement, a core of Coronatite was teleported into a mansion, blowing it into smithereens. Fortunately Alderp had sent all of his servants away for his meeting with Maxwell, and since he was in the basement, no casualties were suffered. However Alderp was distraught when he learned that the destruction of his mansion had been accidentally caused by the adventurer Satou Kazuma, who had ordered that the Coronatite be randomly teleported away from civilization during his battle with the Mobile-Fortress Destroyer.
Alderp, who was now forced to stay in an inn, sort to raise charges against Satou Kazuma as revenge for the destruction of his mansion. Alderp attended the trial, and, when it looked like Kazuma was going to be declared innocent, used the powers of Maxwell to influence the judge. The judge, under Alderp's influence, sentenced Kazuma to death; however Lalatina interjected and told Alderp that she would do any one thing for him if he suspended the trial. Alderp, who was still infatuated by Lalatina, happily complied with Darkness's request.