The Kaidon (or "Clan Leader")  is a Sangheili dynastic rank. The head of a Sangheili State is referred to as "Kaidon." Kaidons are chosen by the previous rulers of the specific state. The Sangheili "Clan Leader" seems to be more of a political position than a military position.
After crowning, it is considered common that any Elder who disagrees with the crowning of the new Kaidon send one or more assassins to kill him or challenge the Kaidon himself, as a form of testing whether the Kaidon is worthy of ruling. Should the assassins fail, the sender is most often executed. One example of this is Koida 'Vadam, an Elder who attempted to have Thel 'Vadamee murdered, but was ultimately beheaded by the Kaidon when the coup failed. However, in cases where the Kaidon is successfuly assassinated, no action is taken against the Elder, as the Sangheili believe that a Kaidon who cannot defend himself is unworthy of leadership. The Kaidon, despite being a political ruler, is still very active in the military, even leading long-running campaigns into enemy territory, leaving the Elders to rule in his stead. Kaidon is a lifelong rank, so the next Kaidon is only crowned after the current Kaidon dies.
- Ripa 'Moramee had a desire for greatness, so he attempted a coup on his own Sangheili Clan Leader on Decided Heart; however, it was a failure. He was punished for this attempt by imprisonment in the Weeping Shadows of Sorrow penitentiary. He was later offered a chance at reclaiming his honour when the Prophet of Regret promoted him to the rank of Arbiter.