By the way, in Heroes 4, in my opinion, it's the most powerful summon. And I also like that in the fourth game you can take several heroes into an army. Especially in Coming of the Storm — each hero is cool individually, but a water army... Better not to mess with them...:rolleyes:
Now regarding leveling. Military Strategy is necessary for ANY hero, as it increases their survivability; if a hero has at least 60-70 armor, first of all, they might not even approach him (speaking of the AI), or if they do start bothering him, he won't be taken down immediately....
But if a hero had even 500 HP but almost no armor, he wouldn't even survive until the second round:)

Барон "Vampires"
Отдай свои прошлые сны,
В сомненьях себя обрети,
В бешеном танце душа кружится!
Не думай, что будет потом,
Здесь и сейчас мы живем,
Стань хоть на миг сам собой, слышишь!