Gonzaemon Katou  

Ironbeard, ゴンザエモン 加藤 芳郎

Gonzaemon Kato was previously the leader of the Bentenmaru and is the father of Marika Kato. In the anime, it's revealed that he faked his death and became an imperial pirate under the name Ironbeard. His family has a long history of serving in both the imperial navy and as pirates. Prior to becoming captain of the Bentenmaru, Gonzaemon was a naval officer. He married Ririka and they had daughter Marika. Later, Ririka left him to raise her on her own. It's said that Gonzaemon passed away from food poisoning just before the start of the series, which led to Marika becoming captain of the Bentenmaru.