Wars of the Wizards

I did not find a specific answer in the thread to the question that arose for me: in a strongly guarded prison (i.e., the hero inside is level 10-30) - will it always be a mage? Or could it be a reduced might hero, resulting in the guard being unreasonably strong?

1) The starting hero can only be a mage (Alchemists and Death Knights are not considered mages. Battle Mages are considered mages)
2) The random starting hero - only a mage
3) Might heroes cannot be leveled above level 5
4) In prisons, there are no might heroes above level 5
5) Red Orb and Cloak of Rejection are banned