What is the name of Mako's younger brother?

Mako’s younger brother is Bolin. The two brothers are major characters in The Legend of Korra and form one of the series’ central partnerships.

Mako is the older, more serious firebender, while Bolin is the younger, more cheerful earthbender. They were orphaned after their parents were killed and grew up together on the streets of Republic City, where they learned to rely on each other.

Their mixed family background reflects Republic City’s multicultural society: their father came from the Earth Kingdom and their mother from the Fire Nation. That heritage helps explain why the brothers bend different elements. Mako and Bolin also compete together as pro-benders before joining Korra’s circle of friends.

A common mix-up is confusing Bolin with Kai, another young character associated with the Air Nation, or with Tarrlok, a politician and antagonist. Bolin is specifically Mako’s younger brother, not merely a teammate or friend.