This idea really has me thinking... and I think it might be possible If a command can set a status ailment on the user and using a skill. Something like this... this is my "real' plan, not the Calbrena idea above.
One of the reasons I wanted to try this out is because I imagine that Baigan might have something similar to this, I'm calling it "Spirit Sword" or rather "SpSwd". Each formation would need changed (at least any formation that he would be in your party to encounter) according to Deathlike2, enemies are normally called from Group 2, now thankfully the game doesn't make a big use of this anyhow. The purpose would be to summon another "ally" to help you.
Using F925, (Attack other random monster besides yourself) is key to this. Each battle formation could have a certain monster that Baigan could "call"with his Spirit Sword ability. But then the problem is... what stops the player from calling more and more? This is where that unused Status could come in handy. Let's say... one were to modify Boast (that does cause the "D" status, doesn't it?) and also give it the ability to call monsters (as the Gird proof of concept shows us).
By inflicting D status on Baigan and sealing the Spirit Sword with D, that will be it's purpose. Then I got to thinking... "How would D be removed?" (Since I plan for Baigan to be a Black Magic user, I don't want Boast to wear off, or have its 16+ to Wisdom). Now, if I'm lucky it wears after battle, that's all on the hope that it's boast. If it is not and it persists after battle, I have another solution, the Golden or Silver Apple could heal "D" couldn't it? I wouldn't want the only way to use this command to have to rest up every single time you want to use it. People would save it for bosses and that would be that.
Of course the Simplest way to make sure that the command isn't abused without additional work is to simply set up the enemies script to kill themselves at the end of their turn. But that limits effectiveness by a great deal.