A Nuatoma is a leader of an Unkalaki family clan on Roshar. Rock describes them as Horneater equivalent of an Alethi Brightlord. The relatives of a nuatoma are his servants. [1]
The specifics of the title like the method of succession and the areas of responsibility of a nuatoma are mostly unknown so far.
Rock implied in a conversation about his people that there is at least one nuatoma for each of the Horneater Peaks and the different peaks might go to war with each other under the leadership of their respective nuatomas.
“ The nuatoma, they see our lack of Shards as a great shame. They want these weapons very badly. It is believed that the nuatoma who first obtains a Shardblade would become king, a thing we have not had for many years. No peak would fight another peak where a man held one of the blessed Blades. ”
Rock's Nuatoma
Rock's nuatoma left the Peaks together with members of his family to gain Shardplate and Shardblade for his clan. He was killed in a duel with Highprince Torol Sadeas for Sadeas' Shardplate. It is unclear what exactly was offered as stake by the nuatoma, but Rock and the other members of his nuatoma's household became Sadeas' servants (and effectively slaves) after the death of the nuatoma.[1]
Some members of the family clan were most likely left behind on the Peaks and did not follow the nuatoma to Alethkar. Kaladin mentions that Rock had sent for his wife in the Horneater homeland after he gained freedom from slavery[2] and Rock says that he will make the other members of Bridge Four part of his family after they all chipped in together to buy him a razor blade for shaving.[3]