Not a Villain[]
I don't think he meets the criteria for being a villain here. He is kinda like Godot who doesn't have a page here. He isn't evil. In fact, he is more so on the good side as he wanted to stop the Professor and went to Stronghart to get Scotland Yard involved but Stronghart being in on the Professor of course refused Asogi's request. He allowed Klint to go out honorably in a duel. While he did murder someone it was in a duel and he only made underhanded dealings because he was promised to be sent back home to Japan. Not anything malicious.