Actually this is a really good idea. Since the Shadowelves use Soul Gems, perhaps the Schattenalfen have found a way to harvest actual souls, through blood sacrifice?
The Pyramid of Corruption
by HåvardThe Pyramid of Corruption is an artifact in the making, equivalent of Rafiel's Chamber of the Spheres. In addition to it being powered by blood/souls, one idea I had last night was that the Pyramid, once completed will drain the Spell of Preservation, rather than magic. Otherwise it will probably function similar to the Nucleus of the Spheres. Does this mean Atzanteotl is aware of Rafiel's plan? Perhaps, but perhaps not. Maybe he has just gained glimpses of it and filled in the gaps with his own ideas? I see Atzanteotl's long term plan to use the Pyramid of Corruption to destroy the Spell of Preservation, allowing the Shattenalfen and Azcans to gain complete dominance in the Hollow World.
Possible effects of drain from the Pyramid:
100 Corrpution Force: The benefits of the Spell of Preservation (abilities etc) stop working for one day per year
500 Corrpution Force: As above, but effect lasts for an entire week. During this time, dramatic events may potentially permanently alter cultures within the Hollow World.
1000 Corrpution Force: As above. 0-level characters loose all benefits.
2000 Corrpution Force: Great beasts (Dinosaurs etc) begin to die. Destructive wars explode among the various cultures of the Hollow World
5000 Corrpution Force: Artifact explodes, causing earthquakes and dramatic volcanic activity all over the Hollow World
Obviously, the Pyramid is not completed yet so none of this may actually occur if the plans of the Schattenalfen Shamans are thwarted.