Motions that units use magic and bows can be changed from "battle animation".
Bow, magic, magic sword etc are range attacks(indirect attacks), so they are defined in Motion 5, 6.
06=Ranged Critical Animation
This is the same as attacking with a magcal sword or a spear , bow , magic.
You can change the range animation motion that triggers when attacked from "Magic Animations" of the item.
If you want to create a new magic, apply the additional magic patch and register the image "Magic Animations".
I think that it is a translation mistake that these are the same name.
In principle, you can not change the flying bow, throwing out, or existing magic effect displayed when you attack.
These are because they are hard coded in the program.
Since these can not be changed, by introducing a magic system patch, you can write it with a script similar to battle animation.
However, for some image data, I know the location.
The throwing spear image data is in the patch.
Magical background data and animation data are found in "Magical animation in ROM".
However, since these are referenced from the hard-coded code, I think that you can not give detailed instructions.
The safest way is to install a magic system patch and implement it.
If you are interested in the program ...
If you want to know the top-level ASM that implements each magic, you can know the address from "Magic Instr Pointers".
Magic is invoked from this ASM, it seems that each corresponding Procs is created and processed.
Procs is very complicated, but if you are interested, read the STAN documentation.
Also, after connecting to the emulator, pressing the Procs tab allows you to see the data of the currently running Procs.