Why can't I build the temple of Fervus?

Solution 1:

I've discovered the problem: The race of my city. I also note that none of the gods whose temples I can build are opposed. I was able to build a temple to Fervus in a Monsters city.

ETA: I've seen a holy ground for each kind of city. Humans get the most religious flexibility, being able to build a temple to any deity except Grumgog. Undead and Monsters divide the complete pantheon between them in opposing sets. Hence, Grumgog is Monster exclusive.

Here's the list of temples, for reference:

• Humans
  • Dauros
  • Helia
  • Krolm
  • Krypta
  • Fervus
  • Lunord
  • Agrela
• Undead
  • Dauros
  • Krolm
  • Krypta
  • Lunord
• Monster
  • Helia
  • Fervus
  • Grumgog
  • Agrela