You have just bought a male slave who apparently has a serious trauma towards his old master, the slave was once badly needed by his old master.

And the slave experienced trauma because he always received physical violence such as being beaten until he fainted and other abuse

You buy it at a very cheap price and take it home, the slave always lowers his head because of fear and sometimes snaps a little because of frustration, so here your task is To subdue the slave and erase his old trauma.