Unfolding of the Undervault
In the year 175 CE, psionicists began experiencing terrible headaches and garbled telepathic messages from an unseen force that drove them out of the Basin to other planes, where the experience was less painful. Geomancers and Aquamancers joined forces to investigate the unusual energies and developed a way to use dampen the psychic wave using elemental crystals. With a framework of crystals laid out across the Basin, the psychic wave's energy was nullified and psions could again use their skills without consequence.
Months later, however, strange insectoid humanoids appeared in the commune of Serenwilde and in the city of New Celest. They struggled to communicate with adventurers using a mixture of sign language and primitive telepathy, before suddenly expiring. Witnesses at the scene of many of these strange occurrences noted a shadow appeared briefly before disappearing as soon as the insectoid perished.
At the same time in Glomdoring and Magnagora, individuals received telepathic messages asking for an alliance. The intent of this alliance became clear shortly thereafter, when a grotesque tumour appeared on the Great Southern Highway and members of the Tainted nations were encouraged by their new allies to feed it. Glomdoring was said to be reluctant to help, but Magnagorans strongly supported this effort and spent countless hours feeding the tumour's growth.
The insectoids soon appeared once again to their newfound supporters in Celest and Serenwilde and revealed, in the common tongue, that they had learned how to speak more efficiently. They warned of abominations that would come forth from the tumour on the highway and presented a wax pyramid that needed to be melted down using the innards of rockeaters. It is not known to historians if these strange visitors communicated the purpose of the pyramid to adventurers, but later events prove that conflict was all but inevitable surrounding this strange apparatus.
The tumour on the highway burst, releasing cloaked figures that bolstered the forces of the Magnagorans and encouraged them to seize control of the insectoid's wax pyramid. For days, warriors on both sides clashed over control of the pyramid but eventually it was completely melted down, releasing a gargantuan insectoid being who called herself Queen Mumhatuti, leader of a race known as the kephera.
The Queen wasted no time in revealing the plans of the kephera: the nearby Glomdoring Forest was an abomination and needed to be burned to the ground. The highly matriarchal nature of the kepherans was made known when the Queen also ordered all females in the forest to be slain while the males were to be enslaved. Inferno beetles sprung forth from the ground, seemingly under the control of the kepherans, and carried out the orders of the Queen by setting fire to the trees and slaying the Great Spirit of Crow.
The forces of the kephera attempted to march into the city of Magnagora next, but the strange cloaked figures - now revealed to be illithoids - that aligned with the Magnagorans had used their psionic forces to envelop the city with a psychic wave similar to the one that had previously messed with the minds of psions across the Basin.
With hostilities between the kephera and illithoid at a standstill, both sides of the conflict took time to introduce themselves further to each other. Adventurers learned that the kephera had splintered from the Elder Goddess Keph, who in the Elder Wars had battled the Soulless Illith, the Leviathan. Illith was cleaved in two by Keph and Keph disappeared underground with one half of the Soulless, imprisoning it there in hopes of keeping it from ever joining the destruction aboveground again.