I'm My Stepbrother's Secret Sub

Ian spends his nights hunting a masked man he calls Fox, the one person he wants under his control. By day he humiliates his stepbrother Leo, unaware the two are the same person. Leo takes the daytime abuse from Ian without protest, then puts the mask back on after dark for the man who wants him kneeling. Family secrets surface and Leo disappears from the house. He returns three years later with money behind him, meaning to make Ian answer for what he did. The two are back in each other's lives and the old arrangement starts to invert. Ian, who once held all the power, finds his position slipping. The relatives who set the original scheme in motion are still working from behind the scenes, and what they started before Leo left has not finished playing out.