Transmigrating into the novel as Ella, a cannon-fodder supporting character doomed by her mysterious illness, she faces imminent death. To survive, she follows the book’s plot and willingly marries the protagonist’s older brother. Royden, feared and shunned by the empire for the demonic blood that flows in his veins, must live in obscurity and endure countless hardships to protect his younger brother. What began as a marriage of convenience—a simple exchange of interests—unexpectedly evolves into a journey of mutual redemption, where two wounded souls find solace and strength in each other.