Roman Sionis

Batman Death Waltz
Over the years, more theft was happening from Sionis Industries. In response, Roman Sionis found out Catwoman's identity, Selina Kyle. First, torturing and murdering her sister, then putting out a hit on Catwoman herself. Roman Sionis enlisted the help of Killer Croc to accomplish this. Black Mask also invested heavily in Jonathan Crane's fear toxin research, favoring it as a very fun torture tool. He met with Crane at Arkham Asylum multiple times to discuss this.

Black Mask and Crane hatched a plot to test the toxin on a larger scale. Attacking the Christmas Eve Charity Ball at Wayne Enterprises. This worked as a chance to kill Catwoman as well since Selina Kyle was in attendance. But he also went after Bruce Wayne, who had blown off multiple business proposals with Sionis Industries in the past. The fear toxin took hold of the pair, Sionis preceded to try to begin torturing Selina, he was stopped however by Bruce Wayne who broke his wrist.

After Crane's capture at the Christmas Eve Ball, Roman locked himself up tight in the Sionis Steel Mill. He wanted Selina to come to him, he didn't count on the whole Bat Family appearing. Black Mask was able to taunt Catwoman over the intercom, getting her to recklessly trigger booby traps in a mad dash to get him. This action injured herself and Batman. It also led to Catwoman being shot in the head by Black Mask. When it looked as though he'd won, Selina spoke and started moving. Startled, Roman tried to fire at her again. He was stopped by Batman and pushed out the office window into the snowy courtyard. Black Mask tried to crawl away to escape Catwoman didn't allow him. This led to a bloody and brutal struggle in the snow. Eventually, Batman stepped in knocking Black Mask unconscious. Roman Sionis was arrested and sent to Blackgate Prison on multiple charges afterward.