List of buildings for the Palace:
1. Slave Barracks - Slave School
2. Mercenary Camp - Training Camp
3. Bivouac - Stable
4. Shrine of Reichor - Minaret
5. Fire Node - Obsidian Pavilion
6. Rukh Nest - Rukh Incubator
7. Pyramid - Great Pyramid
Special building: Mercenary Guild.
Allows you to exchange one type of creature for another, like at a market. It's expensive (ten thousand) and can only be built in a very developed castle (level 13).
I'll write something else soon ;)