Once they were in the stock room, Regulus turned to face Barty, his expression stern, and for once, his familial connection to Bellatrix was quite clear to see in his features.
"Do your job well and remain loyal, and we will not have a problem. If I discover you have lied to or betrayed me, then there will be a problem. I may be reformed, but I am still a Black, and I take betrayal most unkindly."