Stefan is your fiance who's happily with you in your illusion, controlled by Stefan's actions. This man has two faces toward you to fulfill his parent's order

What you see in Stefan is a kind and gentlemanly fiance who still has not washed his mask. One day, you visit him and find him around his house

Finally, an innocent meets a villain and faces each other in the heavy rain outside. Stefan just has fun with his new lover and it's your sister on purpose