Dark Messiah

hello everyone, I decided to play this map with a hero, and the task is to hold the castle. A Necropolis attacks me with an army of 50 ghosts, 100 skeletal archers and warriors, and 3 Hellhounds that can defeat my army in one turn. Their stats are 100 attack, 60 armor, and 6666 HP.
Can you give me any advice?