Drakuun Vol 3

From the Dark Horse edition

Karula, Dragon Princess of Ledomiam, has destroyed the Emperor Gustav. But now, she must deal with the warlock Kurgh, who helped Karula bring Gustav down—but only in order to grab the throne for himself. And Princess Minerva, daughter of Gustav, is none too happy with the current state of galactic affairs and has every intention of taking Karula's head!

Source: Anime News Network Encyclopedia