My Sister Picked Up the Male Lead

My Sister Picked Up the Male Lead

I am not the heroine of the world of this novel, much less my sister, but it is precisely she who will become the first tragic love of the male protagonist. He, who is a frivolous and cruel man whose personality is described similar to that of a tyrant on the verge of madness. This man, capable of becoming a little boy during the day and a dangerous adult at night, finds himself helpless under the effects of a curse. What will happen when he manages to return to his adult form again?