Found the entrance through a portal, and blocked it with another hero, as suggested on the forum. In the end, I completed the map. I got 426 points through the Grail, and after another 7 days, I won by killing the Basilisk, which gave me about 40 more points. It took 14 months. The most interesting battle was against Nagash. Thanks to the Berserker and the Haven faction, I managed to defeat him, although he had 1200 dragons against my 500 Hydras, and the rest of the troops were roughly equal. In total, there were 3 battles that I initially lost, but after making some adjustments, I managed to win. I didn't touch Adrian, and I completed the game with a Swamp Mage, who had almost 99 in all attack, defense, strength, and knowledge stats by the end.