Hartia grew up and trained in magic in the Tower of Fang alongside Krylancelo. They were actually close friends. He's no slouch in the magic department: not as powerful as Orphen but still with great potential in the Tower of Fang.
After the Bloody August incident, Hartia remained by Childman's side, helping out as needed. He's rightfully concerned for Orphen and confronts him now and then, eventually taking on the identity of a comic-book hero called the Black Tiger. As Black Tiger, he rides a giant beast and carries a scythe. However, due to a bad translation, Orphen and company take to calling him Shrimp Man instead.
Still, Hartia is not a bad person: just clumsy and unable most of the time to get the right words out, either though oath or because of circumstance. He realizes that Childman is trying to save (not kill) Azalie, but cannot tell the truth since it would cause Orphen to take a suicidal course, but when the situation begins to change for the worse, he'll reveal himself to Cleao in the hope that she can convince Orphen that their goals are actually the same.