Smart Bomb

Smart Bomb was just a hired gun for the Black Mask, ironically enough he's rather stupid.

Catwoman (Volume 3)
His first appearance was in Catwoman #44, where Catwoman is trying to determine why the East End has remained unaffected by Black Mask, she finds herself presented with a tempting offer from none other than Hush.

In Catwoman #46, as the East End of Gotham becomes flooded with supervillains looking to stake a claim, Catwoman realizes there’s only one way to beat an army of bad guys, is to join them. Meanwhile, Samuel Bradley Jr. has Kellogg in his custody, but Kellogg is saying nothing. The next thing that happens is that Kellogg is dead and Samuel Bradley Jr. takes the mantle.