NR, or the Necromancer, is the Magician of the Dead. Bury stuff, get piety.
Passive: +0.4-2.0 piety for burying corpses. Half piety gain for burying bones and skulls.
Prayer Bonus: Burial of corpses grant +20-+100 flat score. Burial of one corpse also increases the number of ticks of "Impending Death" by 1.
Restrictions: The Necromancer also wants your corpse. Entering pact with NR gives you a buff "Impending Death" that takes 4 turns and ticks downward. If this buff expires, you die and are freed from NR with no additional penalties.
Penalty: Triggered by going negative piety (well, really, impossible) OR by renouncing the god (no longer praying to NR). You are immediately killed.
Non-egotistic: The Necromancer does not care if you pray to another god at the same time. He does want continued devotion though, so there's that.
Decay Factory (4 / +16 / +80 piety) Every corpse buried grants +3 / 8 / 14 points per update cycle.
Fire Resistance (15 / +85 piety) Damage from lava is halved / negated.
[REPEAT] Pestilence: (10+8x piety) Target a player. They lose 20% of their score every turn for 2+x turns.
[REPEAT] Bone Armor: (9+4s piety) Gain one stack of "Bone Armor", which completely negates one source of damage (cannot block lava or "Impending Death")
[REPEAT, CONSUMABLE] Death Defied: (140 piety) Gain effect "Death Defied". If you die by means other than an insta-smite by NR, you are reanimated with 20*piety points, and lose the effect. This effect lasts until you die.