The mountains are inscribed in legend as the home of the first two earthbenders, Oma and Shu, who were lovers from two warring tribes. Despite their peoples' status as enemies, they met on top of the mountain one day by accident. Forbidden from seeing one another, they learned earthbending from the badgermoles and carved what is now known as the Cave of Two Lovers out of the mountains to continue meeting in secrecy. When Shu was killed in the war, Oma became distraught with grief, and unleashed a terrible display of her earthbending powers; however, instead of killing the villagers, she declared the war over. Overcome with an exalted reverence for her, the people abandoned their villages and helped her construct a new city on the site of a mountain, where they would live together in peace. The people named the city Omashu as a monument to the pair's faithful love.
Though the northern and western faces of the mountains are lush and surrounded by temperate forests, the south-eastern faces suffer from a perpetual lack of rain. Small coniferous forests cluster at the base of the mountains, while higher up, this gives way to grassy plains which in turn shrink as the mountains get higher. The peaks of the mountains are rocky and arid, with no vegetation at all. Though the city of Omashu is located within the mountain range, there are no other known settlements in the area.
There is a probability that the name of this mountain range references to the real life Ko'olau Mountain Range located on the Island of Oahu, in Hawaii. The Hawaiian mountain range however, is actually one large extinct volcano.