Murder Machine was created by Scott Snyder and Greg Capullo. He made his first appearance in Dark Days: The Casting #1.
Bruce Wayne is Batman of Earth-44. Bruce watches the death of Alfred (by Bane's hand) over and over again. Following the events of Alfred's death, the Justice League is worried about Bruce. It's certainly normal to mourn when a loved person has passed away, but watching a recording repeatedly isn't healthy at all.
Bruce asks Victor Stone a.k.a. Cyborg to create the A.I. Alfred he’s been working on, even before Alfred’s death. Vic initially refuses to help, but realizes that this will most likely help Bruce in order to cope with Alfred’s death.
The A.I. turns out to be evil and goes on a killing spree killing each and every inmate of Arkham Asylum. Vic tells Bruce that he needs to do something before things get uglier, but more importantly, don't let him in.
However, that is exactly what happens, several A.I. Alfreds surround Bruce and make him the Murder Machine!
As his world crumbles apart, Murder Machine has been killing the entire Justice League barring Cyborg. Cyborg tells him to stop, that there's still humanity left in Bruce.
Bruce doesn't stop fighting him, saying that he has no weakness, he only needs his surrogate father (Alfred), everything else is a weakness he is ready to shed.