Epic Of The Demonic Sage - Chapter 245 - Tainting Dust

In novels with a stud there is always a Senior Martial Brother like this:

In the early stages of the novel, his innate talent is high, his cultivation is good, his appearance is handsome, and he has an intelligent, cute younger Martial Sister as a fiancée.

In the middle stages of the novel, he is caught unprepared and defeated by a young disciple (the protagonist) in the sect who’s hardly remarkable at all. From then on, he falls from his godly altar and loses his brilliance. Even his young Martial Sister leaves him for someone else.

In the late stages of the novel, he continues to turn dark, going down the Demonic Path and becoming the major villainous boss. However, the protagonist still ruthlessly defeats him and his soul is eternally sealed.

Once Qin Mo opened his eyes, he discovered that he had become this Senior Martial Brother.

- Description from Novelupdates

In her past life, Meng Yu couldn't understand why her mother would give the university admission she worked so hard to earn to her younger sister and even sell her off to a remote village as a common wife, just to raise travel funds for her sister.Reborn, Jiang Meng Yu has just escaped from human traffickers, only to be caught by a 'buyer husband'. The fiancé her mother had originally set up for her, whose identity was usurped by her sister, comes to her rescue. She says, 'You saved me, I have nothing to give you as repayment but myself.' Yet when her mother comes, she coolly claps her hands and walks away with her.Captain Gu traps Meng Yu against the wall: 'Flirt with me and then want to run? No way!'Meng Yu resists: 'That was just a temporary measure for revenge.'Captain Gu leans in: 'We've planned everything, let's go with it. I'll help you take your revenge, and you just need to repay the favor.'A slightly silly Meng Yu asks: 'What favor is that?'Captain Gu smirks: 'The life-saving favor that should be repaid with oneself.'Meng Yu: 'Is this fox really the officer I knew in my past life?'

Year 24XX. With several hundred years of improvements, virtual reality has become more mature. It had gradually become humanity’s second world. Socializing, working, studying and other everyday things could all be done while sleeping.

The second prince has come of age. To celebrate the advent of such an occasion, the search for a suitable bride began. My younger sister was expected to go to the Royal Palace as a candidate. However, despite this, she eloped the day before her departure. I, the older sister she left behind, looked almost exactly like her – so much that we were often mistaken for twins…

One month, right? For just one month, shall I substitute in for my sister?