David Cain is a skilled and ruthless killer who works for the shadowy underworld figure known as "Mother".
Mother kidnapped children, brainwashing them into becoming her obedient agents. Using the codename "Orphan", Cain faithfully served as Mother's assassin, and fought Batman when the Dark Knight hindered her schemes for world domination.
Name: David Cain
Marital Status: Single
David Cain was "acquired" by Mother as a child to serve as her personal assassin and enforcer when she first started her human trafficking network. While David was utterly devoted to "Mother" and her ways, when Mother began using Doctor Jonathan Crane's Fear Gas to simulate trauma, David felt that the old ways of "molding" a child through the trauma of witnessing actual death was still viable and sought to prove this to her by secretly siring and molding a child of his own to serve her as a tribute.
Following a theory of his, Cain sired a daughter with the assassin Sandra Wu-San (Earth Prime), kept the child; whom he named "Cassandra", at The Nursery and kept her from interacting with anyone other than him, never allowing her access to verbal communication. This forced the parts of her brain that were normally used for speech to be trained to instead read other people's movements and body language and by extension predict their next move, much like how a person might predict how a sentence would be structured by watching it being created.
Subjecting her to witness numerous killings and slaughters, Cain than forced her to fight various opponents, all of whom she bested. However, when Cain revealed his experiment to Mother, he was berated for his reliance on the old ways and, although he was allowed to keep her, she warned him not to let her see "his pet" again.
Some time later, on September 29th, Mother decided to have David use Cassandra to assassinate the parents of a child named Harper Row as part of a ploy to force Batman (Bruce Wayne) into accepting a "perfect soldier" from her to use as his next Robin in his war on crime. While Batman fell for the ploy, despite his best attempts not to, Cassandra was unable to carry through with the assassination; only managing to kill the mother, Miranda Row, before emotionally breaking down.
Cassandra later escaped her father's influence and fled to Gotham City to warn Batman of Mother's return.
When Cain came to Gotham City to kill the hero Bluebird (Harper Row), Cassandra intervened and cut off his hand. Cain escaped to Mother's Nursery facility in Prague where his hand was replaced by a cybernetic one.
On the apex of her plan to hypnotize the world's children to be her agents, Mother killed David Cain and sent her replacement army of "Orphans" to defend her antenna relays around the world from the Bat Family and their associates.