Series · Kodansha
ONIMAI Vol. 1: I'm Now Your Sister!
Graphic Novel
Nov 24, 2025
Mahiro Oyama was just a normal erotic-game loving dude...until he woke up one morning as a woman! Turns out his mad-scientist little sister, Mihari, tried out one of her new experiments on him...with a disastrous outcome, as far as Mahiro's concerned! But Mihari is as determined to study him as he is determined to go back to his shut-in, game-playing life, and one thing's for sure...life is going to get a whole lot weirder from here on out!
$10.99
ONIMAI Vol. 2: I'm Now Your Sister!
Graphic Novel
Nov 5, 2025
One day, loser shut-in Mahiro was suddenly transformed into a girl by his little sister Mihari, and now he's forced to adjust to his new life as a she! Mahiro explores the new-to-her worlds of the hair salon, the girls' side of the arcade… and even what it feels like to have a crush on another girl?! Can she really hold on to her desire to return to manhood in the face of her new and exciting female life?! This collected edition of the popular gender-bending webcomic will have you rolling with laughter and squealing with delight at this brother-turned-beauty's antics!
$10.99
ONIMAI Vol. 3: I'm Now Your Sister!
Graphic Novel
Nov 5, 2025
Former shut-in Mahiro Oyama was transformed into a girl thanks to his little sister Mihari's experimental drug… and he's starting to like it! But his independent lifestyle is ruined when Mihari enrolls him in middle school! Can Mahiro survive middle school for a second time-and as a girl, to boot?! The brother-turned-beauty's schoolgirl life begins here!
$10.99
ONIMAI Vol. 4: I'm Now Your Sister!
Graphic Novel
Nov 5, 2025
Former twenty-something shut-in Mahiro Oyama was transformed into a girl by an experimental drug… and now he's a seventh grader, too! As he adjusts to schoolgirl life, he begins to take interest in girly topics like Valentine's Day, fortune telling, and even fashion and makeup! But can his idyllic new life continue when someone who seems to know his secret confronts him in the ladies' room?!
$10.99
ONIMAI Vol. 5: I'm Now Your Sister!
Graphic Novel
Nov 5, 2025
This brother has girl power of monstrous proportions! Former twenty-something shut-in Mahiro Oyama was transformed into a girl by an experimental drug, and now he's celebrating birthdays, buying bras, and even turning heads as his exploration of how the other side lives continues! But when the drug starts to lose effectiveness during swim class, can he get to safety without anyone noticing he's not really a she?! The brother-turned-beauty's schoolgirl life faces its greatest crisis yet!
$10.99
ONIMAI Vol. 6: I'm Now Your Sister!
Graphic Novel
Nov 5, 2025
It's his first summer break as a schoolgirl! Former twenty-something shut-in Mahiro Oyama was transformed into a girl by an experimental drug, and every day he's getting closer to being the model citizen his sister hoped to create! From late spring cleaning to early summer homework, gardening to junior high relationships, he can handle it all…but can he survive a trip to the beach with the girls?!
$10.99
ONIMAI Vol. 7: I'm Now Your Sister!
Graphic Novel
Nov 24, 2025
One day, former shut-in Mahiro Oyama woke up as a girl-and his life has only gotten weirder from there! With his second chance at eighth grade summer vacation, not to mention the school festival, field day, and more, he's living his new life to its fullest! Mahiro slowly comes out of his shell, becoming closer to his new friends and even the popular girls in class…plus, he discovers another side to his homeroom teacher that nobody expected! The new life of this brother-turned-beauty is becoming more fun with every passing day!
$10.99
ONIMAI Vol. 8: I'm Now Your Sister!
Graphic Novel
Nov 5, 2025
Big brother has nearly mastered the feminine mind! Former shut-in Mahiro Oyama was turned into a junior high school girl after being drugged by his little sister. While he's still enjoying nerdy stuff like MMORPGs and new game releases, now he's opening his eyes to girly trends like taking selfies and doing makeup, too! On the other hand, Nayutan is suspected to be transferring away, and one of Kaede-chan's classmates has a crush on her! Watch warmly as Mahiro's new comfortable routine goes a little off the rails here in volume 8!
$10.99
ONIMAI Vol. 9: I'm Now Your Sister!
Graphic Novel
Nov 24, 2025
Momma Oyama is on the scene! Former shut-in Mahiro Oyama was turned into a junior high school girl after being drugged by his little sister. But just as he begins to enjoy his peaceful junior high life, his mother comes home from a business trip, and he's suddenly in danger of being found out! Miyo-chan makes a new friend, a New Year's visit to the Nayuta household brings everyone together, and Kaede takes her college entrance exam-all of them continuing to grow, one step at a time, in volume 9!
$10.99
ONIMAI Vol. 10: I'm Now Your Sister!
Graphic Novel
Jan 27, 2026
Former shut-in Mahiro Oyama has now fully embraced the junior high school girl life. As his circle of online friends expands, he might even get in-game married?! Throw in a little snooping into Kaede's life as a college freshman and a little sex appeal to manipulate the boys at the arcade... All this and more, as Mahiro discovers the joy of expanding his horizons through forming connections with his friends in volume 10!
$10.99
