Mako is kind of like the Katara equivalent in The Legend of Korra. He’s a fire bender that eventually joins the Avatar on her quest to save the world. He’s a decent character but he just wasn’t the character I think they were hoping for.
He originally was a professional athlete among benders. Mako eventually becomes a cop and then a bodyguard. But I thought his original profession was the most interesting.
It was actually his romantic relations that remained in my memory after a few years of watching the show. His first big romance was with Asami Sato which definitely ticked off Korra because she had a crush on him too.
He eventually breaks up with her and gets into a relationship with Korra. But their relationship just wasn’t meant to be.
While he still helps her out when he is needed, they just decide to be friends. Korra actually ends up in a relationship with Asami Sato, which is ironic.