Planescape Canonical Campaign
Pillar of Skulls
The Pillar of Skulls, located in Baator, Avernus, is a large column of living heads and skulls The heads once belonged to those who possessed knowledge, but chose to tell lies. These lies led to the deaths of others or otherwise caused enough harm to earn this punishment. Because of this, the Pillar is a great information repository. It can answer many important questions, but its information is not free. In return for answers, the Pillar demands payment in the form of sacrifice.