How to Turn a Gentle Male Lead Into an Obsessive Male Lead

I became a supporting villain character who torments the male lead and then dies in a suspicious carriage accident. Since I was destined to exit the story without much significance beyond tormenting him with cruel words while living in the same house, I had planned to simply go with the flow, aiming only for ‘survival’… but… The male lead, Atan Casaros, was an ominous little boy unwelcomed by everyone, and somehow, I couldn’t just stand by and watch him... It was partly a calculation to avoid being disliked, and partly a meddling born from sympathy... He who should have dreamed of a happy ending with the female lead, having the keyword of a ‘gentle male lead,’ “Forever and ever, I’ll hate only you, Noonim. So tell me that you’ll hate only me forever too.” He began to obsess over me... Source: NU Includes 23 extra chapters.