Playing on Green Patch led me to discover that you can teach Skills to units, however there is no evident way to find ‘how’ without being able to peek inside Green Patch. I would go myself but I can’t tell my right from my left with how Japanese Rom and English Modules works on each other.
Proof:
As you can see, I taught her the Charge skill to allow her to have potentially infinite strikes.
This is a tall task as it likely require a rewriting of ASM to allow FE8 to be in line of FE4 and FE5’s skill trees. It’s possible as Japanese has demonstrated but it’s feasible at best with our small understanding of these until Brendor can pull something more concrete out of his ass than skill writing.
Also, it seems no one has found or made evident that you can promote via weapons.
Sothe of Green Patch is currently the only one that I found is capable of this:
A further digging into Nightmare and Modules reveals that you can indeed make this a reality.
Simply move to Item Editor via FE7 and I’m certain FE8 also function the same way, find an promotion item move to Use Effect, that is where the effect come from. You can add this to a weapon with a promotion effect of your choosing as long as you adjust the original promotion to work differently to prevent potential bugs.
I have yet to test it because I don’t have anything to work with right now.
Go big, guys. Who know what you might find out.