[Endoperez]

Slave Matrix is an item that makes its wearer act as if he has cast Communion Slave/Sabbath Slave. That is, they will share the fatique and even boost magic levels of those mages on the battlefield who are under effects of Communion Master/Sabbath Master/Crystal Matrix.

What, exactly, are you trying to get your commander to do? If you want him to not run away from battle, try giving him Slave Collar. I haven't used it myself, but it should stop anyone wearing it from running away from battle. The item can't be removed.