Who is Geoffrey Wylie from The Warrior Heir and what is their importance?

Geoffrey Wylie is a wizard, who is in pursuit of the Shadowslayer. He is described as a tall man, with angular features. His beard covers the lower portion of his face, and the top half is blistered, looking as if he's been burned. Wylie's voice is dry and unemotional. He is a procurer for the Red Rose, and can be vain