МОД: Клинок Армагеддона / Armageddon's Blade

Here. I tweaked it a bit and configured everything as needed, using the Gremlins as an example. A dummy creature wasn't needed. https://disk.yandex.ru/d/GTNgAi5kZwGIHg Now, there's a bug where the actual cost of upgrading to the third level is zero.

Added 30 minutes later
In short, in addition to what I wrote earlier, you also need to specify each other in the upgrades for the third-level upgrades.