Moku was a nomad who traveled with Chong and Lily through the Earth Kingdom. A happy, easy-going, and rather obese young man, he played the djembé, a small drum which he kept on him at all times in order to strike up a song whenever it was needed, and was quite talented at it. Moku wore a white robe with pale pink edges and a cone hat called a caping which was decorated with a small pink flower. He had a fondness for rainbows and was also rather naïve, being unable to make the connection between a "big campfire" and the Fire Nation soldiers pursuing them. He also felt no need to fear being trapped in the cave, his childish simplicity ensuring he remain optimistic that he would find a way out, or eventually be rescued from the cave.
Moku met Team Avatar whilst the latter were relaxing in a river close to Omashu. He bonded with Aang and Katara straight away due to the airbender's relaxed nature, and during the brief respite even suggested an alternate route to Omashu once it was discovered that it was where his newfound friends were headed. After Sokka shot down this suggestion, stating that they didn't have the time, Moku traveled with Team Avatar, Chong, and the rest of the nomads through the Cave of Two Lovers when it became apparent that Appa wouldn't be able to fly them to Omashu. At one point, a cloud of wolfbats frightened Appa, causing the bison to panic and bring down the roof of the cave, thus resulting in the separation of the group into two different factions. Moku's group consisted of the other nomads, Sokka, and Momo. Using his djembé, he and the rest of the party managed to calm down two irate badgermoles with music, and with the animals' help were eventually able to escape the cave. After leaving the cave, Moku was asked by Aang whether or not he wanted to visit Omashu with Team Avatar. He politely declined the offer, preferring to travel with the rest of his nomadic friends, before parting ways with the group.
Moku was very socially naïve. He lived in a world of his own for much of the time, only speaking when he had something he deemed necessary to add, such as his love of rainbows and fascination with campfires. Due to this relaxed nature, Moku got along rather well with Aang, as the airbender seemed to appreciate his simple perspective on life. Moku did not seem to care at all for punctuality or places, instead finding a simple life of traveling and playing music to be rewarding enough. Because of this attitude, Moku was at odds with Sokka, whose over-zealous nature was in direct contradiction to the easy-going nomad's. He never picked up on Sokka's irritation, unable to comprehend that the Water Tribe warrior found his lack of planning and timing to be undesirable. Despite this, Moku parted ways with Team Avatar on just as good terms as when he met them.