I was attacked by Drakkens of level 9 units, although mine were level 3. I saw they had 7.5 exp per turn. I checked everything but still couldn’t find how to increase the units’ experience per turn. Only the hero’s skill gives +1 to his units and the building gives +2 when in the city. Can you tell me all the possible options for increasing units' exp per turn??

Can you tell me all the possible options for increasing units' exp per turn?        

Winning battles gives Experience) Do you have the dlc with access to Auriga's Altar? Or rather, do you have all the dlc? Do you have the dlc with access to Auriga's Altar? Or rather, do you have all the dlc? Maybe there are some “improvements” in there. Check out the technology of the Last Era (5, can't remember exactly). Deeds that you get when you move to the next Era.