In the hero's mansion you can train a hero. For this you need a normal soldier who will become the hero and therefore you need a barracks or a stable.
When the building reaches levels 10, 15 and 20 you can annex 1, 2 and 3 unoccupied oases with your hero. Depending on the oasis you will get an increase in production for a certain resource (or even two resources for some oases).
construction time for level 1: 700 | 670 | 700 | 240 | 2 | 0:38:20
