Given the isolation of the Kaaranese Sangheili from their Sanghelios brethren, and the Covenant in general, until 2123, it is surprising that their native religions and beliefs are so similar, in that they revere the Forerunners as god-like beings worthy of veneration, their relics left behind for their followers to learn from. There are a number of differences, such as interpretations of the Great Journey and the role of individual non-Forerunner spirits in its achievement, but for the most part the Forerunners have gained the same amount of reverence that they hold among the rest of the Covenant.
This is largely due to the influence of Thoth 'Keltam, an ancient citizen of the Keltash Empire before its fall in 400 BC. Though remembered as a "seer", a religious holy man and envoy of the Forerunners, it is more likely that Thoth was simply a scientist studying excavated ruins near the Keltam Peninsula. His studies are the first recorded mention of the Forerunners, and his notes were remarkably few - massive structures and smaller relics created by an ancient race of such technological sophistication that it was impossible that they were created by the far more primitive species that inhabited the planet before the Kaaranese Sangheili drove them to extinction. His conclusion was that it was an ancient race, perhaps that which had led them to Kaaran, unintentionally sparking a religious revolution among Keltash culture. New religious orders and sects sprung up seemingly out of nowhere, demanding the relics be consecrated as sacred ground. Others urged their destruction, seeking to protect the old gods they worshipped. Thoth himself tried to start a secular organisation to objectively study them, but attracted more zealots than he cared for, forced to scour his recruits to ensure only the brightest entered his inner circle. Religious conflicts were most restricted to regions near relics, but there was never a satisfactory conclusion - the eruption of Mount Keltam rendered the entire point moot, destroying the relics and the people who contested them.
Thoth himself was not present during the eruption, and may have been overseeing the excavation of relics further away from Keltam. However, his return to the former empire was a sad one, with little in the way of surviving relics. Worse still was the devastation of the cities and towns that surrounded Keltam, and the ensuing ecological disasters - floods and droughts, and fluctuations in climate that were as destructive as the eruption itself. In desperation, most fled across the seas to Kaaran to start a new life - Thoth was not one of them, but he sent most of his acolytes along with the Exodus. Exactly what his fate was has never been determined - some insist that, disillusioned and distrought, Thoth sought solace in solitude, living his life quietly in isolation. Others claim that he continued to study Forerunner relics, and that he continues to, having achieved immortality. Still others venerate his spirit as a guardian of Forerunner sites, and as a messenger for the Gods. It is likely that Thoth would have been disgusted, being a self-confessed athiest himself. He would probably have been more pleased at being regarded as the father of Voltakran Alchemy, and in turn modern Kaaranese Science.
- "The Cult of Quenyathar and Bringers of Holy Light revere him as a spirit of knowledge and learning. Ironic, since in life he was quite critical of religion as an institution. Even as a spirit he's apparently still cynical - "No use praying to Thoth, he doesn't believe in prayer!""
- "Odd coincidence, sharing a name with an ancient human knowledge deity."
- "Occasionally, a supposedly recently discovered "Second Journal" will crop up - usually by a religious fanatic, intent on using Thoth to promote their own cult."
- "For a religion that supposedly doesn't have gods of its own, it has enough Prophets."