MTL - Unique Legend - v5 Chapter 3 Mysterious tenants

The handsome, noble, cold, and ruthless family heir Ignatius Leclair took a liking to the fostered girl Delphine Carter in his home.From then on, the aloof man transformed into a loyal companion, taking care of children, cooking... The entire aristocratic circle was utterly shocked, with everyone envying.Delphine Carter smiled serenely: cunning, energetic, vengeful, a different persona by day and night.[Reading Tips: 1V1, both protagonists are pure, sweet story, the heroine is beautiful.]

After accidentally falling, she actually finds herself bound to a Second Female Lead Counter Attacking System!

This story is about a rookie researcher, who was forcefully dragged away from his restful life, compelled into facing various killers and zombies, always having to risk his life at the brink of death, and finally becoming an advanced researcher that is acclaimed by all. And throughout his adventure, he met an alluring(?) killing machine, who he started to have fantasies on after they had an accidental kiss…

Xiao Yan: Did I fall for him? But he’s a man!

Maya: Who knows…. maybe it’s the other way round?

- Description from Novelupdates