This study analyzes the role of willing self-sacrifice in Guy Gavriel Kay’s trilogy The Fionavar Tapestry. I begin by detailing anthropological studies about sacrifice which provide the critical framework for this thesis. I contrast Kay’s trilogy with J.R.R. Tolkien’s The Lord of the Rings trilogy and claim that they have fundamentally different worldviews. Tolkien’s worldview is primarily providential where every act of free will only reinforces the plan. In Kay’s trilogy, free will is often counter to a divine plan and acts of free will can and do alter that plan for the better. I analyze the trilogy by focusing on specific instances of willing self-sacrifice in each volume and showing how those instances either alter the divine plan, in this case The World Tapestry, or result in its successful completion. I draw the conclusion that Kay approaches the problem of fate and free will differently from other fantasy authors, specifically Tolkien, and that he takes a more secular approach to the ideas of sacrifice and free will.