Girion

One of the Vyrs that serves as an advisor and aide to the Vye, ruler of Undyr, Girion is an old, wise, and well respected man. While he tends to keep to himself, and looks rather unimposing, he often has wisdom to offer when his lord calls on him for aid or advice.
What none of the people of Undyr know, is that this unassuming man is actually a demon in disguise. One of many preparing the way for an invasion from within, Girion is the leader of this invasion, making subtle suggestions and decrees to set the stage for a larger play.
His eyes and ears are everywhere, and as an advisor to the ruler, he knows every going on in the entire empire of Undyr. Information he uses to fill in the details of his plot, and find the exact right places to strike when the ideal time comes.
Even now he and his agents work towards that goal, making suggestions that seem on the surface to be to Undyr's aid, but secretly set it up to be weaker in the future. The with Galayin is a particular point of interest, though it is not in Girion's goals to cause Undyr to lose that war. Rather, he seeks to prolong the war, so that both Undyr and Galayin can take as much damage from it as possible, leaving them both in a weakened and vulnerable state that he and his demon can capitalize on.
Beyond his wit, he has powerful magic of charm, illusion, and divination, allowing him to better gather information and manipulate that around him into doing his bidding, without them having the slightest idea they're working for him at all.
While his influence is great, the Vye himself still controls Undyr, and Girion is but one of his advisors. A well trusted one, but even still Girion seeks to carefully grow his influence and power until it challenges that of even the Vye himself.