Undercover by the Villain's Side

Transmigrated into a cultivation novel as an undercover spy, I'm sent to infiltrate the villain's faction by the righteous Immortal Alliance. My mission? Gather intelligence and await the signal for the final battle. But years pass, then decades—I rise from lowly disciple to elder, then Left Protector, climbing the villain's ranks while my handler keeps saying "wait a little longer." By the time the Alliance Leader finally calls for battle, I've become the villain's most trusted lieutenant. Now the righteous sect wants to fight my boss, and I'm caught between two worlds with nowhere to hide. S…