From ROI Wiki

Regnig is the servant of Negago and is second in command after Segarg. He is the vice commander of Negago's army and serves under Segarg, with whom he has a strong, somewhat tenacious rivalry, as Regnig seeks to some day take Segarg's place as Negago's chief commander. His preferred weapon is a powerful cat-of-9-tails whip that he uses with nearly the same effectiveness as a sword, and of which is equally as deadly. However, between him and Segarg, he is the weaker warrior and less skilled fighter, as well as being less skilled at strategy and tactics as well compared to his senior commander. But, that doesn't stop him from wanting Segarg's job.