Yeah, that's right. NAGA_TEMPLE. If you place this object on the map, it will appear as if there is a guard and a reward from the elementals' bank, but that's not the case. The Naga Temple has its own parameters in the creature bank properties, which by default copy the elementals' bank. So, this is a free slot.
Plus, there's another slot for creature banks. There are two types of wrecked ships in the game (among the bank characteristics). Both are used, but if you give all the ships one type, the second will become free and you can use it for your own purposes.
Cool! Nice find!
Added 1 minute ago
yes:) I struggled a lot with them - the Lich has a flawed skeleton, and the models on the hands were severely deformed, so I had to stretch the arm 4 times to compensate for the growing bicep.
Added 1 minute ago
I'm probably going to expand the list of neutral demons, and maybe even turn the dragons' utopia into a static Inferno. Cool!

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Неудачное планирование ведёт к неудаче ...
NCF - мод, добавляющий дополнительных существ в HeroesV 3.1