"240H" – unlocking new heroes and improving existing ones.

I took some screenshots.

Well, this is how you use effects!

And how do you make something an effect?
I only have Paint and Notepad as tools.
I meant, which file do I need to edit for this, Character or Model?

Well, any static effect is a model (a three-dimensional shell) in the game engine's format, but for your idea, these models will also need to use animations! For a better understanding, I recommend downloading the latest version of NHF and looking at the heroes of the "Haven" faction - for example, how the heroines Mirabelle, Gabrielle, and Ornella are implemented - the "driver" = effect, and the "transport" is a standard model with a transparent standard "driver," Isabelle!

You can do it in any editor, BUT to get the file in the game format, you need to have Alias Maya 6.0 installed on your computer (6.01 will also work - search on this forum, someone has already written that they have it)!

Then you will have to thoroughly delve into other mods (from simple to complex, to understand the internal structure - there is nothing too complicated, you just need to want to and you will succeed)!