In theory, you could level up to 80, though the game is easily finished by the time you reach level 5 or 6. And heroes were only troublesome: expensive, crappier than other mages and their "abilities" to inspire the other mages didn't work.
Loved protector 1 and 2 but this one needs serious amounts of tweaking.
 "Protector III"){kind=icon}
 "Zening"){kind=icon}