The Devoured

The Devoured, known as Ran'darin before his death, was the son of the elf god Corellon. He entered into a relationship with Lolth, the Spider Queen, despite his father expressly forbidding it. Together they create the drow. The relationship predictably went badly for him when Lolth killed and consumed him in their bed. Eventually, the Drow collect slaves. The slaves begin hearing a voice in the depths of the mines where they are being kept. Some learned how to understand the voices, and the slaves are able to subsequently free themselves. 
Unbeknownst to Kiono, the seals were used collect his essence in a long term project to revive the Devoured. While the original goal was presumably to revive someone they were grateful to, it has been twisted by their isolation from the world.