Walkthroughs for custom maps.

When playing as Necromancers, towards the end of the game, pay attention to the number of skeletons in a single unit: there cannot be more than 32767 of them – neither by adding troops normally nor as a result of a battle! Otherwise, a numerical overflow may occur, and the number of skeletons will become negative!

This is not true. I played with units of several hundred thousand – on the Ira the Mage map, with a total playthrough of 2000+ (!!!) MONTHS.

You just need to carefully "move" these units between slots so that they don't "reset".

For example, in a town, you cannot simply move such a unit from the upper slot (garrison) to the lower slot (hero) without it resetting. But you can detach, say, 30k units from the upper slot and add them to the same lower slot. This way, you can move a unit of any size.

There are other nuances, but, I repeat, units larger than 32767 are perfectly viable.

Added 2 minutes later
upd
I suspect that the upper limit of the unit size is limited by 31 or 32 bits, i.e., approximately 2 (4) billion units.