Phantasm

"Your Angel of Death awaits."

- Phantasm

Andrea Beaumont a.k.a The Phantasm was Bruce Wayne's love interest and the main antagonist/anti-hero of Batman: Mask of the Phantasm.

Before Batman
Bruce Wayne was visiting his parents' graves at a Gotham cemetary when he met the beautiful Andrea Beaumont. They quickly fell in love and began spending time together. At the same time, Bruce was also beginning to fight crime as a masked vigilante, but no one was scared. He decided that bats were scarier and attempted to be 'Batman'. After stopping a street robbery, Bruce gets hurt and Andrea is frightened. Bruce returns to his mansion, angered, as he "can only have one or the other, I can't have it both. I can't go out doing this if I have someone waiting for me to come home every night!" He decides to choose love over crimefighting and proposes to Andrea. She accepts at first, but the next day, she returns the ring. Saddened, Bruce ultimately dons the mask of Batman.

Return
10 years later, a mysterious masked figure (who would become known as the Phantasm) begins slaying various mob members related to Valestra starting with Chuckie Sol in Gotham City. Because of the dark appearance, the Phantasm is mistaken for Batman and the Caped Crusader is now on the run from the police, attempting to clear his name. Salvatore Valestra went to the Joker and pays him millions of dollars to kill Batman. The Joker later kills Valestra. The Joker learns that Andrea is the Phantasm. Andrea is killing the gangsters for the following reason:

Andrea wanted to marry Bruce, but Salvatore and his gang was pressuring Andrea's father to give them the money he owed them. He knew he would be unable to do so, so he and Andrea moved away to the Medditerranean Coast of Europe to hide. Her father eventually paid them. However, it apparently wasn't enough and when Andrea returned home after buying groceries one day, she found her father slaughtered. She was killing Valestra's gang as revenge. Bruce (as Batman; Andrea knows his identity) confronts Andrea and asks her "what will vengeance solve?" Andrea responds "if anyone knows the answer to that Bruce, it's you!" A battle then ensues between Batman and the Joker and the Phantasm and the Joker disappear into the night, the Joker laughing as it happens and Batman escapes an explosion. Batman thinks that Andrea, his one true love, is dead when in reality she escaped to a cruise ship where "she is alone".

Future appearances
The Phantasm appeared in an episode of Justice League Unlimited. She was hired by Amanda Waller to murder Terry McGinnis' parents, but couldn't bring herself to do it.