Hazanko, Leader of the 108 Stars and commander of the Anten Seven. Hazanko is a leader in the Kay Pirates, a massive group of pirates who control large regions of space. He is one of a number of pirates who work directly under the Tendo King (the high commander of the pirate group), and is apparently one of the most powerful, both militarily and in terms of personal capabilities. His title "Leader of the 108 Stars", is never explained, but it actually conceivable that he is in control of 108 star systems. A space station that he owns is shown in one episode, and it seems to be quite sizable (as a rough estimate, 10 to 100 kilometers across).
In addition to controlling a gigantic military operation, Hazanko is not someone you would want to annoy. He is an exceedingly powerful magician (one of my favorite things about Outlaw Star is the mix of technology with magic, similar to Shadowrun), and can (and does) easily tear people to pieces with nothing more than a wave of his hand. His personal ship, the Geomancer, is as large as a military cruiser, and carries a number of powerful magicians to aid Hazanko, along with a nice complement of conventional weapons.
Hazanko, with the surreptitious help of the military, built the XGP-11A-II (AKA the Outlaw Star) and it's navigator, Melfina, to find the Galactic Leyline for him. Even with all the pirate's power and money, they did not have the access to sufficient technology to build a ship as advanced as Outlaw Star without help. After the Outlaw Star was stolen, Hazanko wanted the ship back, and the military wanted it destroyed so their involvement with the pirates would not be revealed. Hazanko seeks to overturn the Tendo King and eventually take over the galaxy. The only way he can gain this kind of power is through the Galactic Leyline, and the Outlaw Star is the only ship that can successfully enter the Leyline.
Hazanko eventually does make it inside the Leyline, and is granted the power he seeks. However, with the help of Melfina (who has interfaced directly with the Leyline), Gene Starwind and the crew of the Outlaw Star manage to kill Hazanko before he can leave the Leyline and cause chaos throughout the galaxy.