Arthur Reeves is the tertiary antagonist of Batman: Mask of the Phantasm and a corrupt city official who was once an intern for Carl Beaumont. He later becomes involved with Valestra's gang in order to gain the influence to enter City Council, and told them where his former boss was hiding in return for campaign funds. Years later, the Phantasm was killing the mob and this caused Arthur to have the police hunt Batman, thinking Batman is doing the crime. Another reason, when the mob gets killed by the Phantasm, Arthur is worried that the (still thinking it's Batman) Phantasm would go after him and he'll lose the money the mob is funding him. When Batman got away from the police, Arthur is angry about it. The Joker tracks him down and the Joker wanted to know who the Phantasm is and the Joker says that Arthur knew about the mob and sold Carl out to them. Joker thought it was him until Andrea called and Joker figured out that Andrea was doing it. Joker poisons him with Joker venom. He appears in the Gotham City Hospital, having been driven insane by the Joker's chemicals. Batman confronts Arthur and he demanded to know why Joker visited him. Arthur told him his connections to the mob. Arthur never knew that Andrea was the Phantasm and he never knew about the Phantasm. Batman leaves him and not curing him as punishment. In the comics, Arthur's face never recovered and he became deranged. Andrea manages to kill him by having him to jump off the skyscraper and thus getting her revenge on him for selling her father out.
Reeves was quite a selfish, arrogant young politician who, although seemingly in love with Andrea Beaumont, let her father get killed by a hitman who would later be the Joker. Reeves was not only corrupt and a puppet to the mob but was also quite nervous and anxious when his life would be threatened. He began to sweat and pant when the Joker was threatening his life, proving that he clearly was scared and desperate for his life. He would do anything to save himself and did not care about what would happen to others.