I've this question since I play this game 13 years ago. It seems that AI will not use certain hero in skirmish mode.
such as dragon's garrin, serpant's budo.
and why is that happened?
what can i do to make AI use these heros?

Actually i found out the reason.

Take necromancer as example.

all you have to do is go to Data_UnitToWarPartyEffectiveness

and select Type 50, 51, 52 and set value for each columns like assault,raiding,defense..etc

(in this case number means possiblities, if you set higher the unit will be more common AI use it)

In doing so, you will find out AI will add Necromancer into their troop.




The reason why AI will not bulid necromancer is because the Type 51(zombie) , 52 (spirit warrior) all the column number are zero, which make AI not deploying..

This is just a post of appreciation. Thank you a lot for sharing this info with others.