Fullmetal Alchemist: Brotherhood: Bring It On

Alex Armstrong and Olivier Armstrong staring angrily while covered in blood

Don’t mess with Major General Olivier Armstrong or her younger brother Major Alex Armstrong.
From the anime series Fullmetal Alchemist: Brotherhood


Gakusen Toshi Asterisk: Students of the Yellow Dragon

Shenhua Li and Shenyun Li wearing pink fighting clothing

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)

Taimadou Gakuen 35 Shiken Shoutai: Bedside Manner

With her head on a pillow, Kiseki Kusanagi looks up at and holds the hand of Takeru Kusanagi

Even though Takeru Kusanagi’s little sister, Kiseki, has dangerous (and sometimes uncontrollable) magical abilities, he will do anything for her sake simply because they’re family.
From the anime series Taimadou Gakuen 35 Shiken Shoutai (AntiMagic Academy 35th Test Platoon)

Eve no Jikan: Memory

The Sakisaka family, as viewed by their new house android, Sammy

In a time when androids are used as everything from construction workers to housekeepers, Naoko Sakisaka sees them as mere things, while her younger brother Rikuo’s views change over time.
From the anime series Eve no Jikan (Time of Eve)

Amanchu!: Merriment

Makoto Ninomiya and Ai Ninomiya wearing wetsuits in front of a polka dot background

When Ai Ninomiya is not busy kicking her younger twin brother, Makoto, for fun, the two enjoy going scuba diving.
From the anime series Amanchu!

Diving into 2017

Happy New Year from Sister/Brother Complex featuring the Ninomiya siblings in Amanchu!

Image from the anime series Amanchu!