regarding the collection of skeletons in "Mr. Skelet Revenge".

...So, share your secrets if you don't mind :)

Here are a few tricks I used:
1) Before attacking an enemy Castle, I would send them money. The next day, they would hire an army that they couldn't have hired due to a lack of funds. And this army soon turns into glorious skeletons :)
2) Of course, visiting Demon lairs, abandoned mines, and griffin conservatories. If anyone hasn't noticed, at the end of the path, there are 3333 Archmages. That's quite a few skeletons too.
3) While playing, I left a few of the computer's Castles "alive," and towards the end of the game, I destroyed them (when I had a larger army).

In my army, I only had Archangels and skeletons. I increased the magic power for reviving skeletons. I also increased intelligence.

To keep the Demon lairs, abandoned mines, and griffin conservatories untouched by the computer, I left the Castle for 2 weeks and 2 days with Liches and skeletons. I sent other heroes to take over the remaining Necropolises.
In the first green Castle, I researched the second-level Mage Guild (which gives the Blindness spell). After that, skeletons didn't get lost at all during battles.