sibling rivalry   (兄弟の競争)

He was also spurred on by sibling rivalry with his elder brother.

He credits sibling rivalry with sparking his initial fascination with cartooning.

The film evolves into an exploration of family, sibling rivalry, coming out, and reconciling with the past.

younger sibling   (年下の兄弟)

He has 3 older siblings and one younger sibling.

He is the younger sibling to sister Ayesha.

His mother raised Benitez and a younger sibling as a single mother.