In the Grasp of a Loving Yet Possessive Male Lead

I was reincarnated as the younger sister of the villainous Archmage, who is destined to be executed by the male lead. To avoid dying, I've been trying to reform my villainous brother, and so far, I've managed to survive... Why are you here?! The male lead is collapsed in front of our villa? I couldn't just leave him to die, so I brought him in for now... but the male lead's condition is a bit strange. "Kiss me, Rose. If it's not you, I'll die." "Rose... please, I need you. Save me..." I'm just the villain's sister, though? Why on earth is he doing this to me?! Unable to ignore the dying male lead, I eventually helped him... "Let's get into a deeper relationship, us." "Excuse me? A deeper... relationship?" "Kissing, and other things too..." He looked at me with an agonizing expression, pulled me close, and trapped me in his embrace. With a blindingly bright smile. "You're my first, Rose." O-oh no, you shouldn't be saying I'm your first!