Hehe... The mobs is this game isn't wery evolved.
The trolls last thought "hey look at that guy over there, he just took out ten spiders, 28 ratling and 7 salads. charge!!!"
But it is no wonder that they dosn't evolve. Only the weak who dosn't enter the battle field survives, so what do you think would happen if only handicapped (mentally/physically) trolls were to reproduce them selves?
Rhetorical question, no answer needed