At some point, Cyrus fell in love with Luther's wife, Queen Philomena. Consumed by hatred for his master, he schemed with the magician Ardath Dastagir to kill Luther by sabotaging a ritual meant to grant him supernatural powers.
During the ritual, Cyrus made a deal with the Magician, asking to be forgotten about so he could leave his old life as champion behind. The Magician instead made it so everyone who encountered Cyrus forgot him immediately afterwards.
Unbeknownst to others, Cyrus has spent the nine years since the ritual working quietly as the palace gardener, a job which enables him to remain close to Philomena even though she no longer remembers him.