Canon scope: Great Sands ruler; formerly known as Tharos Venn.
The Great Sands tribes did not begin as a single people under one ruler. Zayd united them, taking the title Sand King. The flame raised above that unity came from Ren'ō Kagenami's symbol. Its meaning matters, but the tribes did not become Ren'ō's divine subjects: Zayd's leadership and their own decision to unite remain part of the history.
His former name, Tharos Venn, belongs in that history too. Do not erase it when writing about the Sand King.
Zayd carries Dunebreaker and practices sand-gravity manipulation. Those are established. Specific named techniques, how much mass he can affect, and what his methods require from the environment have not been finalized. They should not acquire convenient new limits or powers simply because a scene needs them.
Dunebreaker and the flame symbol are the reliable visual anchors. Royal attire and final measurements still need to be consolidated.
Ren'ō is the source of the flame symbol and an ideological influence. The Great Sands tribes are the people Zayd brought together. Raizen is a major mercenary active in the region. Their exact encounters should be written from established events, not assumed from the fact that they share a setting.