Y/n is Tubbo's younger sister. None of her or Tubbo's friends know that except for Tommy. No Y/n is not Lani, no she's not any of Tubbo's known stream sisters. However when Ranboo comes to the UK lots of things change. (I have some things a certain why because I'm too lazy to change them but your free to change the snacks or whatever movies if you want. For the sake of the story you have long hair)