Thanatological rituals
The rituals PERFORMed by a Necromancer on corpses and corpse parts are their primary source for learning the Thanatology skill.
Preserve (1st circle)
The preservation ritual does basically what its name implies, preserves a corpse so that it will not decay at the accelerated rate species of Elanthia (that are not adventurers) seem to enjoy. A preparatory ritual for other things, the preservation ritual will make a dead body last much longer, or until SKINned and SEARCHed. Utilization of this ritual requires/teaches some knowledge of first aid, and prevents the Harvest ritual. As of 8/23/2015, successful PERSERVEs generate Divine Outrage.
Harvest (2nd circle)
The harvesting ritual allows a Necromancer to carve a piece of a corpse out for personal use to some diabolical end at a later point. Doing this ruins any possibility that the corpse could be skinned, but perhaps the Necromancer achieves some higher benefit from it later. Utilization of this ritual requires/teaches some knowledge of skinning, and cannot be done if the corpse has been SKINned.
Fetish (3rd circle)
The only ritual that is not performed on a corpse, this blasphemous ritual imbues a necrotic item that the Necromancer is holding with the power of death. It is presently unknown what uses these fetishes hold, or how many variants there are. Initial observation suggests that the item must be properly set up beforehand, and this ritual is just the final touch.
Cut Hand (5th circle)
Using your ritual knife, you cut your hand (non-damaging) to act as a component for Necrotic Reconstruction, Quicken the Earth, and Blood Burst.
Dissection (10th circle)
This ritual is purely an educational tool. This ritual is performed on fresh corpses which have not yet been SKINned or otherwise ritualized. When used on the corpse of a formerly living being, it teaches a mixture of Thanatology and First Aid, more so than preserve teaches. When used on the corpse of a formerly undead being, it teaches pure Thanatology. This ritual does not generate Divine Outrage.
Consume Flesh (15th circle)
Requires a corpse to be present (PC or NPC). To heal a part on yourself, the corpse must have its corresponding part not already destroyed. The ritual will destroy the corresponding part on the corpse while healing it on the necromancer. This is not actual consumption, but a magical effect.
Arise (20th circle)
The most time-consuming ritual in the Necromancer's arsenal, the ritual to Arise is performed just before the sorcerous magic needed to imbue a corpse with false life is enacted. The corpse in question must have already been PRESERVEd.