In order to avoid attending a school known for having Japan’s worst delinquents, Hikaru Onigashima switches places with his younger twin sister, Hinako Nakayama. Fortunately, she’s good at hand-to-hand fighting.
From the anime series Kenka Banchou Otome: Girl Beats Boys
Kazuha (male) and Karuha (female) are twins who became spirits after dying against their will. When the war god Bishamonten took them under her care, they gained the ability to turn into weapons she could use to fight harmful Phantoms.
From the anime series Noragami
The aggressive Carossa and the cautious Melissa are twins who fight for the Claw Man as members of The Original Seven.
From the anime series Gun x Sword
Yoko Inokuma loves her little brother Kota and little sister Mitsuki, even if the young twins say they don’t like her. They’re big liars, and she knows it.
From the anime series Kiniro Mosaic (KINMOZA!)
Biscuit Griffon works for a private security company (and then a mercenary group) in order to make enough money to support his family and send Cookie and Cracker, his younger twin sisters, to school.
From the anime series Mobile Suit Gundam: Iron-Blooded Orphans
Twins Rosalind Lutece and Robert Lutece are both physicists who are, had been, and will be one of a kind.
From the video game BioShock Infinite
There are eleven children in the Loud household: Lori the eldest is always on her phone; Leni the second eldest is fashionable and ditzy; Luna is a rock musician; Luan is an aspiring comedian; Lynn is an athlete who loves sports; Lincoln the middle child is the only boy; Lucy is a pale-skinned goth; Lana is a tomboy who enjoys building and fixing things; her twin sister, Lola, loves wearing pink dresses; Lisa is a child prodigy, and Lily is a baby.
From the Nickelodeon series The Loud House
Yuuko Kinoshita and her younger twin brother, Hideyoshi, might look identical, but they’re quite different. She’s an intelligent, prideful, and irritable member of Fumizuki Academy’s top class, whereas he’s a helpful and kind individual whose true passion is acting.
From the anime series Baka to Test to Shoukanjuu
Buranki are giant, sentient, robotic beings, and both Azuma Kazuki and his younger twin sister, Kaoruko, have the power to awaken and use the one known as Oubo, though they disagree over who has the right to possess its control-unit “heart.”
From the anime series Bubuki Buranki
Shenyun Li and his younger twin sister, Shenhua, are both arrogant and ruthless but highly skilled fighters who enjoy making their opponents suffer in the arena.
From the anime series Gakusen Toshi Asterisk (The Asterisk War: The Academy City on the Water)