Apokalimon
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That's a logical question, but why would you even need to change anything if the final Knight will be a copy of the original creature, and vice versa, and you initially have the original creatures that have simply exchanged their artwork?
This leads to the question: who would do it, and why, if it doesn't really make sense?
Honestly, it's a silly question.
Added 2 minutes ago
A mod / map / or anything else is essentially a renamed zip archive in the form of a .pak / .h5u / etc. file.
You can open any mod with WinRAR / 7z / or another archiver, go to GameMechanics / Creature / Creatures / (Necropolis / Neutrals) / name.xdb..., and simply change the parameters.
Added 1 minute ago
In general, this forum thread is very strange. It seems like you can place an order for any mod, but in reality, whatever you ask for is either too difficult, too easy – do it yourself, or why bother, or justify the purpose of the mod... So, explain what mods you can actually place orders for