Who is Orbix Xaxis from The Last of the Sky Pirates and what is their importance?

Orbix Xaxis is the novel's antagonist. He is the Most High Guardian of Night, and he lives in the Tower of Night where Cowlquape is imprisoned. Orbix allows Xanth to go to Lake Landing to spy on the Librarian Academics, his sworn enemy. Orbix Xaxis suspects a plot when he sees Rook's signal to Twig at the Tower of Night. Orbix is described as tall and imposing, and he wears dark glasses to repel any who try to curse him with the evil eye and a metal mask to purify the air he breathes.