Oma and Shu were two lovers from feuding villages that were forbidden from seeing each other, but after learning Earthbending from the giant badgermoles, they went on to build an elaborate tunnel system in order to continue meeting in secret. Shu is killed during a conflict between the villages and Oma then uses earthbending to unify both sides, thus Omashu is founded.

The two lovers are originally male and female, but the adaptation 'netflixes' the couple into being two females instead. This of course has caused a stir between all sorts of opinionated folk. Personally, I found the change to be a half-assed attempt at inclusivity, it felt like someone just CTRL+F'd all the male descriptors and replaced them with female ones. It's as if the series doesn't already have plenty of representation they could have pulled from. Hell, they had Kyoshi on screen, they could have easily given her a line about "protecting your loved ones" and shown Rangi.