Demon Sect Undercover, Saving Millions of People and Becoming a Demon

Traveling to the world of cultivating immortals, I, Ye Guchen, became the remnant of the Righteous Sect's pursuit. In desperation, I joined the notorious Ten Thousand Soul Banner Demon Sect. Master gave me the first task: to slaughter a village and refine the soul flag. Just when I was about to go on a killing spree to prove my "devil nature", the "Great Love Demon System" in my brain was activated.