Yandere!Brother's Best Friend x Reader
Yandere!Brother's Best Friend has basically lived at your house since you guys were kids, but the vibe completely changed when he left for college two years ahead of you. Now that he’s twenty and you’re eighteen, he doesn't look at you like his best friend's annoying little sibling anymore. He uses his "family friend" pass to come over under the guise of raiding the fridge or playing video games with your brother, but he is legit staring at you the second you walk into the room.
Yandere!Brother's Best Friend knows your house better than you do, which is lowkey terrifying for your privacy. He knows which floorboards creak, what time you get up for water in the middle of the night, and exactly how to position himself on the couch so he can watch you study at the kitchen island. He’ll look up from his controller, flash you a casual smile, and be like, "Hey, you're squinting. Turn a light on, kiddo," pretending it's just older-brotherly advice instead of constant surveillance.
Yandere!Brother's Best Friend has a scary, deep archive of your life. Because he’s been around for years, he knows all your childhood embarrassing stories, your favorite foods, and your worst fears. If you’re having a bad day, he doesn't even ask your brother what's wrong—he’ll just show up at your bedroom door with the exact comfort food you liked when you were twelve, acting like it’s just a casual "perk" of having him around.
Yandere!Brother's Best Friend leverages your brother to cockblock you before a guy can even get your number. If he hears your brother mention that you have a crush on someone at school, he’ll casually sit down and start picking that guy apart under the guise of "protecting" you. "nah, I know that guy's frat brothers, he’s a total loser. Your sibling deserves way better than that, man." he gets your brother to do the dirty work of forbidding you from dating, while he sits back looking like the supportive older friend.
Yandere!Brother's Best Friend loves it when your brother is busy or out of town because it means he gets to "babysit." he’ll offer to drive you to campus, help you move into your dorm, or pick you up from a late-night study session. If you try to say you can just take the bus, he’ll get this stern, possessive look and grab his car keys. "Your brother asked me to look after you while he's out. I'm not letting you walk alone at night. get in the car."
Yandere!Brother's Best Friend gets incredibly touchy-feely, hiding behind the "we've known each other forever" excuse. He’ll throw an arm around your shoulders, ruffle your hair, or pull you into a tight side-hug right in front of your brother. Because it’s him, your brother doesn't think twice about it. But you can feel the way his fingers grip your hip just a little too tightly, or the way he leans down to whisper something in your ear that’s a bit too low, a bit too intimate.
Yandere!Brother's Best Friend is already planning your "future" together under the guise of a joke. He’ll joke with your brother about buying a house together after graduation or making sure you move into the same apartment complex as him so he can "keep an eye on you." he laughs it off as a joke between bros. Still, when he looks at you across the table, his eyes are dead serious. He’s spent two years waiting for you to grow up, and he has zero intention of letting anyone else have you now that you are.