Reincarnated as the Yandere Villain’s Little Trickster

Chi Yu has transmigrated. She becomes the once-glorious daughter of the White City's lord, now the male protagonist's cast-off wife, a frail and cunning little schemer. She has a history of heinous acts such as poisoning the female lead, assassinating the antagonist's beloved, and humiliating the physically imperfect, sickly antagonistic great demon king, among other shocking deeds. In this hellish starting situation, the first task issued by the accompanying system is: —— Save the world. Chi Yu solemnly declares: 'It seems my destiny is to be a savior. The road ahead is long and has no end; I shall search high and low!' Just over ten minutes after her oath, her skull was crushed by the great demon king... Chi Yu: '???' Are you kidding me? Is this difficult level even worth playing? Is this a useless system just daydreaming! 'I'm dead, the story ends with a shower of flowers.' System: 'No, you can be resurrected infinitely until you complete the mission to save the world.' ... Half a month later. Chi Yu meets the great demon king again and is pierced through the chest by his sword. Another two months pass. She is held in the great demon king's arms, used as a human shield. Chi Yu: '... (inexpressible frustration).' Five years later. Chi Yu, enduring humiliation and with a strong will despite her physical disabilities, successfully revives the love line of the original male and female leads, inspiring them to suppress the great demon king and save the world. She leaves quietly, hiding her name and deeds, and 'dies' in the great battle... However, her 'death' leads to a total collapse. The great demon king goes berserk, slaughtering everyone. System: '... I don't know what went wrong either, shall we try again?' Chi Yu: '#@$% System, you don't have a mother.' PS: Despite the brutal description, this story is 1v1, with a main sweet and pampering love line, and the plot is satisfyingly silly (with some special settings that may be a bit harsh on the female lead's body). The male lead has no 'white moonlight' (a metaphor for an unattainable love interest), only loves causing trouble in the first life, and only likes Chi Yu in the second life."