HIMOUTO! UMARU-CHAN, by Sankakuhead. First published in 2013, and first published in North America in 2018.
PLOT:
To the wider world, Umaru Doma is the perfect high school girl. Pretty, poised, brilliant, and talented at every task she sets herself to, she is the envy of every kid in her class. Once she gets home, though, she becomes Umaru-chan: a selfish, lazy otaku who pigs out on junk food, torments her brother, and manipulates him to get her way. The only thing that Umaru works harder at than being a pest is keeping others from discovering her true self, but a strange silent classmate might ruin all of her work in a moment.
