Rumor

Mario was formerly Paul Karon's bodyguard, but after failing to protect him, he became the vigilante Rumor.

History
When Paul Karon was introducing his latest invention, a device that shoot low sound vibrations that could destroy buildings, he was attacked by Joker, who wanted the device for himself. Batman arrives and stops Joker, but fails to save Paul Karon from being crippled. Mario feels so guilty, he begins to rectify his mistake by capturing all of Gothams great supervillains and execute them. Using the technology he captures, Killer Croc, Hugo Strange, Man-Bat, Bane, Poison Ivy, Black Mask, Mr. Freeze, Spellbinder, Firefly, Ragdoll, Temblor, Cluemaster, Gearhead, Harley Quinn, Kabuki Twins, Killer Moth, Punch and Judy, Ventriloquist and Scarface, and Rupert Thorne. Penguin trips an alarm at a Museum on purpose so Batman can arrest him. However Batman could not stop him from taking Penguin and Catwoman, but he did get a small piece of the suit, identifying Paul Karon's company as its creator. While Batman first suspects Karon, he soon realizes it was Mario. Meanwhile Mario captures Joker and attempts to exectue them with a giant version of Paul Karon's sound device that Joker tried to steal so long ago. Batman and Robin arrive to defeat Rumor, but accidentaly caused the release of all the other criminals. Batman and Robin fight them all off to save Mario. Mario is sent to jail with the rest of the criminals, except Catwoman and Hugo Strange, who managed to sneak away.

Powers and Abilities
Mario utilizes Paul Karon's technology, including an exosuit that enhances strength, speed, and allows the user to be invisible. He also uses a battle staff that discharges electricity and shoots projectiles.

In other media
He appears only in The Batman episode 'Rumors'. Originally Hush was intended to be the villain, but DC did not like the idea, and created Rumor in his place.