Alfonse and Sharena, the prince and princess of the holy kingdom of Askr, battle against the invading Emblian Empire.
From the video game Fire Emblem Heroes
What happened to respected ace pilot Ralph Werec? His little sister, Sara, follows in his footsteps and joins the military in order to find out.
From the anime series Soukou no Strain (Strain: Strategic Armored Infantry)
Theodor Eberbach and his step-sister, Lise Hohenstein, are pilots in the same East German battle squadron during the brutal war against the BETA alien invasion, so they keep an eye out for one another.
From the anime series Schwarzesmarken
Don’t mess with Major General Olivier Armstrong or her younger brother Major Alex Armstrong.
From the anime series Fullmetal Alchemist: Brotherhood
Hayato Kisaragi fights dangerous alien life forms known as Savages in order to get the most advanced medical treatment for his wheelchair-bound younger sister, Karen.
From the anime series Hundred