...Congratulations to DeadLord on the victory...
I didn't hold back against the Knight; I killed him on day 2. As a result, on day 3, I released one hero from the starting Castle and three more from the Knight's Dragon Castle to go after the Unicorns. Of course, they had to travel on foot, and as a consequence, on the way on day 4, I lost my starting Castle and the Sorceress. On day 4, I liberated my home Castle, killed the invading hero, and recruited the Unicorns. The hero with the Dragon runs towards the Sorceress's Castle, killing another Witch along the way. The hero with the Unicorns doesn't manage to escape with them; rather, he doesn't even make it to them, stopping just a few steps away... Meanwhile, the heroes released from the Knight's Castle defeat one Barbarian hero with the help of Centaurs and Gargoyles gathered from the Necromancer. In total, by the end of day 4, there are 7 heroes in the army.
Day 5. The hero with the Dragon lays siege to the Sorceress's Castle... and goes to "level up." The Unicorns are delivered in a chain to the southern front, where a Barbarian hero is killed.
Day 6. The hero in the north captures artillery and "finishes leveling up."
The Barbarian hero, who had retreated quite a distance to the northwest, is defeated by crossbowmen. Another Barbarian hero, deliberately left untouched on day 5, runs towards the Knight's Castle and stops a few steps from the lumber mill. Another hero emerges from the Barbarian Castle... Both are defeated, and the Castle is taken.
For reasons I don't understand myself, I got carried away with the tertiary criterion. The result: 6/12/32