The Exile
The Exile is an event where the Spirit Valley Tribes have been compelled to flee their homelands by the Spirit Wilds. The event has been highly disruptive to the culture of the tribes and saw many casualties, as well as the beginnings of new culture and religions to understand what had happened to them. Upon entering various established powers, the tribes' presence would lead to violence and discrimination frequently.
Pre-Exile Context
While the location of the original homeland of the tribes is now understood to be the southern banks of the Spawn Lake, outside contact with this area was fairly limited. As a result, we know very little of tribal culture prior to the Exile. "Codices of the Southern Tribes", an attempt to study the tribes by the Church of Fire, cites a "former Othii general" who describes their old way of life as such:
Our people thrived in the homeland we can never return to. The land was bountiful, and we lived in harmony with the trees. We took enough land for crops that we might feed our people, but we knew to leave enough for the trees such that we might hunt. Our warriors were mighty, and our people stood strong. There were many tribes back then - we sometimes warred, we made peace, we married. Nothing is the same.
The same general notes that, while his parents did live in the homeland, he was born during the Exile. In this account, he also states that spirit raids were a regular but minor issue, and that the regular attacks of the Wilds were "once in a generation ... every week, soon every night". We can discern here that there was a hostile relationship between the tribes and wild spirits from this, but one where the tribes were either superior or at least equal.
In the context of the Exile, the Tribes are often split into two groups: East, consisting of the Othii, Carnii, Kaerii, and the now-extinct Senerii; West, consisting of the Toshkii and Galethii. No other tribes are known at this moment.
We were not the only ones forced to flee. We never heard from our cousins to the west, as we were split forever by the spirit hordes. Some tribes elected to stay, whom we never heard from again.
It is clear from the Codex's account that this division did not seem to exist prior to the Exile, being more of a regional identity than a distinct ethnolinguistic group. Most accounts of the Exile seem to state that the Spirit Wilds began their attacks from inside the homeland, pushing outwards. As the sea contained the northern and southern perimeter, this forced tribes to move in one of two directions, East or West. This separation is likely what caused the split.
Eastern Exodus
The Eastern Exodus consisted of at least four tribes: the Carnii, the Kaerii, the Senerii, and the Othii. Their period of exile was marked by an extended period crossing swamps. During this time, multiple events took place which massively shaped the culture and faith of the tribes in the years to come.
Existing sources indicate that the swamps were infested with spirits, but said spirits were influenced by local wildlife and thus were very passive at night time, seeking to preserve energy absorbed from the sun. As a result, night time became a period of calmness and security, while daylight hours represented ferocious conflict. This period played a crucial role in fostering the Cult of the Moon, which is conventionally believed to have originated within the Carnii, who interpreted the security of night as a protection from the seemingly otherworldly light of the moon. This faith soon spread as this principle was true of all other tribes in the crossing. The Cult of the Moon would survive the Exile and be continued once the Eastern tribes exited the swamps, and is still practised in secret to this day in spite of heavy Church of Fire repression.
Contrary to more romantic pan-tribal narratives, the Exile did not represent a period of unity for the Eastern tribes. Indeed, it is unclear if the tribes are not themselves a product of the Exile, as all accounts state that while regions and families were associated, the boundaries between different people's in the homeland was far blurrier than it is now. While this debate continues, it is undoubtable that tribal affiliations were formed during the Exile, as there are numerous reports of conflict between them even while the Exile was ongoing. This was largely believed to be in competition for extremely scarce resources, settling old feuds, scapegoating others for having brought the spirits upon them (primarily directed at the Kaerii), or to consolidate power in a time of crisis.
The Senerii, led by Arkala, were the most successful tribe during this period in seizing control through conflict, having been comparatively less devastated than the other tribes. Rather than fighting pitched battles on canoes with a very limited pool of male warriors, Arkala instead targeted the women of rival tribes with bribes, blackmail, and underhanded means of establishing influence over them and their male relatives. This tactic worked, with the family unit holding particular weight in the midst of so much death, bringing vast numbers of warriors to Arkala's banner. Recognising that threatening his army's mothers was not a strong recruitment tactic, these relationships were largely tributary and extractive in nature rather than hegemonic.
Upon landing on solid ground, the Eastern Tribe's period of exile can be said to have come to an end, with new territories carved out from the land and their former homes abandoned forever. This new status quo would not last long, however, as this disruption of regional power would prompt the War of the Flowers with their northern neighbour, the Fire Nation.