Originally Posted by
Jackalope89
Pre-Flashpoint, he nearly killed Steph. Shortly after, Jason came in and basically destroyed his empire from the ground up, either by taking those that worked for him or killing those that wouldn't defect in UTRH. Basically unintentionally avenging Steph (and I believe Selina delivered the killing blow to Black Mask later).
In Rebirth, Mask had some device in the Mayor that Jason neutralized under the guise of shooting him. Then Mask tried to use Biz for a puppet, which then backfired, and last we saw, Black Mask was in Ma Gunn's care. Alive, but essentially a vegetable. Due to his own actions.