Rituals of Mud: Rebirth

The Beast Tribes of Fallen Imbrifel are extremely well versed in druidic lore and magics. Their forest home is a wellspring of Fey energies and earth magics. The Tribes’ female spirit shamans have mastered the arts of reincarnation. Using the mud of the forest, they are able to bury their fallen warriors and shamans to see them reborn. Each body is submerged into the holy mud on certain nights and with the proper sacrifices and prayers, a new being arises with the soul of the buried individual at dawn. Many also possess some of the memories, knowledge and skills they had prior to death. Female shamans rises as young boys who become warriors, warriors laid to rest there rise up as their tribes spirit animal (and sometimes exceptional varieties of them), and those same spirit animals will be reborn as female infants destined to become shamans. As the generations of reincarnation continue, the tribes become larger and more potent in their abilities.
The tribes also use the mud rituals as a way to dispose of capture enemies. Those buried alive undergo strange transformations that not even the wisest shaman can predict. Whatever form they arise in, sometimes with memories and abilities intact, are considered holy and revered. Those that are transformed this way are known as the Earthborn.
These rituals have lead to an overcrowding issue within the Tribes. The reincarnation plus the nature birth rate outstrips those deaths that are final (the shamans decide not to reincarnate or their is on body). The increasing population has taxed the local food supplies. The tribes have responded by increasing their territories and by increased raiding. Both of these actions have lead to conflicts with neighboring tribes.