Walkthroughs for custom maps.

Six-thousanders can be given a Book of Earth, then there will be a Town Portal.

Added after 17 minutes
By the way, Eagle Eye was used during the walkthrough of Qin the Supreme. I didn't remember it right away for some reason.

Added after 1 hour 34 minutes
I also thought about the option of preserving the Cloak of the Undead King. If we don't give away the Cloak of the Undead King, then Gunnar isn't freed, we don't get Luna access to the tower, meaning we stay on the necro lands with Luna until the very end of the map, when someone brings the Book of Earth. At the same time, there are several quest guardians that only Luna can open, so it's unclear at first glance how critical the consequences of such a decision would be. It seems that Isra with Vidomina on this map are specifically geared towards building a skeleton army, not liches :)

If Vidomina, in theory, can be freed a bit earlier by surrendering the Might of the Dragon Father, then Isra is freed after killing Monere (for the necklace +3 to stats and the Alliance of Angels), and that's essentially almost the very end of the map already; by then, whether with the Cloak of the Undead King liches or without it skeletons, there won't be many targets to raise them from (except maybe intentionally leaving some neutrals alive). I, by the way, considered the option of making skeletons from all the creatures of levels 1-4 (or maybe 5-6) from all castles, and from dragons and hydras - bone dragons. It would have turned out nicely (maybe 30-40-50 thousand skeletons, as well as 1.5 - 2.5 thousand bone dragons), although I didn't calculate their exact number, since the active army still looked more appealing.

But the final battle can probably be fought without Hytran, by gathering skeletons, bone dragons, possibly black knights, and putting on the Armor of the Damned with the red ball :)