This is the taboo version of Whatever He Wants.

Isaac
My little sister is totally off-limits. But all bets are off when her boyfriend steals something from me. It’s only fair I take something from him in return: her. By any means necessary.

Denise
My big brother has always been my protector, but one selfish act changes him from someone I admire to someone I fear. He’s ready to ruin my life... unless I give him whatever he wants.

Whatever My Brother Wants is a spicy taboo age gap romance. It features a morally grey hero, power imbalance, push/pull tension, and ends with a HEA.