easy map on hard difficulty, first learn vampirism: 1 defense, 2 increase HP. Throughout the entire campaign, I developed the Necromancer. In my opinion, strengthening necromancy with the necromancy talisman and sacrificing at the mage's tower is effective, and the Dynasty weapon was Soul Eater. At the end of the campaign, I reached level 5. I played the campaign on hard difficulty in both the Steam and Book versions.

Added 3 minutes later

Okay! I'll try to find it today! But the map on "hard" is tough!! Because the SPIRITS don't heal if they are not upgraded, starting from patch 1.5.1.

Why use necromancy for healing? It's a racial ability, and even though it's weak, it helps a lot + vampirism will prevent you from dying, and you'll be able to play confidently without losses if you start developing the Mortuary properly, even in patch 1.5.2.