Christina Bell (Earth-4678)

"If you try to come between us. I'll carve you a smile so wide your head falls off."

- Christina Bell, to Commissioner James Gordon

Christina Bell was a succesful financer who joined the board of directors at Queen Industries in Star City. During a blood transfusion following a miscarriage, Christina was exposed to the Joker's mutated blood. When she returned to work, Christina took a knife to a board meeting, brutally murdered eleven senior executives, and carved smiles on her victims' faces. She adopted several facets of Joker's personality, notably his obsession with Batman.

Source

 * https://arkhamcity.fandom.com/wiki/Christina_Bell