All characters 18+
Part One:
![Cuckoo: Get Adopted For Profit! [Man to Girl AR] by Transviscera](https://images-wixmp-ed30a86b8c4ca887773594c2.wixmp.com/f/87684d17-8b34-4054-a6cc-9b9e97dcb44a/dgykhxy-7d619ead-33d4-48c1-87ef-bb0cc3ff54ce.jpg/v1/fit/w_150,h_150,q_70,strp/cuckoo__get_adopted_for_profit___man_to_girl_ar__by_transviscera_dgykhxy-150.jpg?token=eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJzdWIiOiJ1cm46YXBwOjdlMGQxODg5ODIyNjQzNzNhNWYwZDQxNWVhMGQyNmUwIiwiaXNzIjoidXJuOmFwcDo3ZTBkMTg4OTgyMjY0MzczYTVmMGQ0MTVlYTBkMjZlMCIsIm9iaiI6W1t7ImhlaWdodCI6Ijw9MzkxMCIsInBhdGgiOiJcL2ZcLzg3Njg0ZDE3LThiMzQtNDA1NC1hNmNjLTliOWU5N2RjYjQ0YVwvZGd5a2h4eS03ZDYxOWVhZC0zM2Q0LTQ4YzEtODdlZi1iYjBjYzNmZjU0Y2UuanBnIiwid2lkdGgiOiI8PTg4NDcifV1dLCJhdWQiOlsidXJuOnNlcnZpY2U6aW1hZ2Uub3BlcmF0aW9ucyJdfQ.mAdCEuOnF-0hZOoBLH1xJdVAngFYWmHQgdL6BU5IXNg)
So you've got yourself a brother. That's bad news. If he senses that you're there to get your hands on his parent's affections (i.e. money), which he will, he is going to do everything in his power to evict you from your comfortable new family unit, and make your life hell in the process. Your only hope is to negotiate with him or, failing that, get him evicted first.
Thankfully, you're the new arrival, which means you have a several-month grace period during which (in your adopted parents' eyes) you can do no wrong. Leverage that time for all its worth. Antagonize him whenever they're not around. He's onto you, so don't try to hide it. Flaunt it. Describe to him at length how you plan to spend his inheritance. Invade his personal space. Wear the most provocative outfits you can to drive his blood pressure and testosterone through the roof. Tease him outrageously. You know how the male mind works, so use that to your advantage.
Keep at it long enough, and he'll act out. This is your chance to start driving that wedge between him and his parents. Vitally, your character must be beyond reproach, so that his accusations appear to come from a place of jealousy, or even an unhinged mind. For that reason, it's important to maintain the facade of a perfect daughter to everyone but him. Only once you've got the house to yourself can you relax and enjoy the fruits of your labor.