Yes, as it says in the modding manual, you should be able to do it.

I went over the mod manual and although it mentions that, it doesn't actually touch on how to make one.

You could pose the question in the main thread about modding.

Sorry no you can't create new paths or add spells to paths. I've wanted to do same thing. Weapons have very similar properties so whatever you want to do should come close but you can't take advantage of spell system that allows to gain and lose spells with libraries.

Well I've read through all I could and no, it seems spells are not moddable at all up till v4.18 at least (Marlin's executable dumps are really really awesome I can't even begin to thank him for them and would have saved myself some time if I began my search there). I'l try and check if there's been an update to this for v4.21.

Edit: Just as I submit this, the page refreshes and my comment became useless just like that ahah.