Adding unused skills (Return, Re-move, Recover...) to characters

[God of Humility]

I'm trying to add those skills to some characters or classes and I'm wondering if its at all possible. I figure its not because it doesn't appear in the selection in Nightmare, but there seems to be a corresponding icon in their description on this site so it got me wondering. My guts tell me its not feasible, but the game has icons for them and this site lists them in the same section as Holy/Darlness Sword which are accessible.

Anyone knows anything about this?

[Agro]

I'm... pretty sure this is easily done. It might not appear in the selection simply because whoever made them (Pukachi?) didn't account for them. But I remember being able to put them in using that other dodgy FE4 editor program so it's definitely possible.

[Darros]

I'm trying to add those skills to some characters or classes and I'm wondering if its at all possible. I figure its not because it doesn't appear in the selection in Nightmare, but there seems to be a corresponding icon in their description on this site so it got me wondering. My guts tell me its not feasible, but the game has icons for them and this site lists them in the same section as Holy/Darlness Sword which are accessible.

Anyone knows anything about this?

I was once screwing around in FE4 Nightmare, and all those Unused skills under the third skills dropbox seem to have effects like that. IIRC return is somewhere in that list. None of the unused skills have icons though.

[God of Humility]

Its just as you said. The skills are active, but the icons don't show. When I tried using those "unused" skills in Nightmare, they showed no icon, so I just assumed they were empty since on this site, those skills have an icon and in-game, Holy Sword and Darkness Sword have an icon to show they are there.

Anyway, thanks for the help, both of you.