After Becoming the Villain, is the Younger Sister the Savior?

[Dual perspectives from both male and female leads] + [Urban setting] + [Slow burn] + [Sister complex] + [Original content] + [Minor nerfs in post-production]

Eight years ago, a "virus" codenamed "Demon Gu" broke out worldwide. No one knew where it came from, only that new infected people would appear every now and then.

Infected humans undergo mutations in certain parts of their bodies, gaining extraordinary abilities. They hide among humans, feeding on the flesh and blood of their own kind. The relevant authorities call them "Demon Seeds".

Jun Ye, who lost his sight in childhood, regained his sight while in his senior year of high school and became a "Demon Seed".

Just as her father remarried, she inexplicably gained a stepmother and a sister with no blood relation.

Having joined the villainous organization "The Seven Deadly Sins," codenamed "Pride," he recently discovered that something is off about his sister.